Art. LVII.—Rabbit-disease in the Wairarapa.
[Read before the Wellington Philosophical Society, 27th June, 1888.]
I wish to place on record the facts connected with the outbreak of rabbit-disease in the South Wairarapa, and the methods by which the rabbit-pest was conquered in that district, as a guide for other places, especially insular lands of the globe.
Early in the year 1884, finding that our poisoning operations to reduce the pest were proving futile, and not caring to erect rabbit-proof fencing around my land to protect myself from my neighbours, I determined upon calling the settlers together for the purpose of simultaneously taking proper measures to grapple with the evil. The pest had been worst with me during the years 1881–83, but by 1884 I had personally managed to get it down so far as my own run was concerned. The settlers met upon the 19th April, 1884. A voluntary system of simultaneous action was resolved upon, and I am pleased to be able to say now, in the year 1888, that the pest has been thoroughly conquered over the whole district. The rabbits now only require watching, as they are watched in any country of Europe.
The measures the neighbours adopted were simultaneous poisoning with phosphorized grain and the simultaneous turning-out of the natural enemy, chiefly the ferret. A few of us. had been previously poisoning, and breeding and turning out ferrets, and some of us the domestic cat; but the Hon. Mr. Waterhouse was the first to turn out a few ferrets, some four or five years previously. In 1886 Mr. E. J. Riddiford preferred turning out stoats and weasels upon the land, and I think he turned out two to three hundred (one hundred stoats and two hundred weasels). From 1878 to 1888—say in the ten years of the pest—the measures taken, therefore, to grapple with the evil were hunting and shooting with dog and gun, poisoning with phosphorized grain, and the turning-out of cats, ferrets, stoats, and weasels. Seeing that we were turning out the natural enemy, I induced the settlers not to make use of traps. At the present moment so little is this question understood that a reference to Mr. Bayley's (the Chief Rabbit Inspector of the colony) annual report for 1888 will show that the Government and every Rabbit Inspector are willingly allowing the use of traps in every other district of the colony. Of course this is almost fatal to the natural enemy. The use of traps must be absolutely prohibited. With regard to rabbit-proof fencing, I always thought it a
weak thing, and I would have nothing to do with it. I preferred to reduce the pest upon my neighbours' runs as the best method of protection for my own land.
Time ran on; the rabbits were disappearing fast, the lands were becoming clear; and now a rather great factor of suppression appeared—I suppose I may say the greatest of all—viz., disease—bladder-worm or tape-worm of the dog, concerning which the facts are as follows: Early in the year 1886 I had noticed that my rabbiter's pack of dogs were looking miserably-poor, half-starved, mangy skeletons. I spoke to the man, and told him that I could not allow him to keep his dogs in that condition. (I had now only one pack of dogs employed: formerly, in 1882, I had four. I think I sent home about one-quarter of a million skins during the pest.) I had previously noticed that a neighbour's pack of dogs were in much better condition, and that neighbour's rabbiter had told me that he gave his dogs areca-nut to relieve them of worms. I advised my rabbiter to give his dogs the same medicine. And, although Professor Thomas, in his late report, tells me that I did wrong in giving the dogs this medicine, yet must I, from practical experience, say that to it, and the consequent dissemination of pieces of the tape-worm all over the run during the last two years, can I alone attribute the thorough infection of my land with bladder-worm or rabbitfluke. The diseases of liver-rot, scab, and lice also appeared. The few rabbits that I have remaining are now nearly all diseased. I may perhaps have been wrong in administering monthly doses of the medicine—two-monthly doses would have been better; but that the mistake was not fatal is proved from the fact that the run now is thoroughly infected with the disease. I therefore still advise runholders in the South Island to each use a pack of dogs, feed them upon raw rabbit during the week and boiled rabbit upon Sundays, and give them two- or three-monthly doses of areca-nut. For I must respectfully ask scientific men, like Sir James Hector and Professor Thomas, to concede a little to practical experience in this special matter, seeing how great the evil really is to be contended with. (A reference to Professor Thomas's report will show that that gentleman lays great stress upon the efficacy of the winter poisoning in my district. All I can say is that the winter poisoning did us very little good. Under it the rabbit-pest was as bad as ever.)
About eight or nine months since my rabbiter informed me that he had applied to the New South Wales Government for the reward offered for a proper method of suppressing the pest in Australia. His suggestion was, infection with venereal. I did not believe in this, and considered in my own mind that the disease I had upon the run would be a
better thing for Australia. We often discussed the matter amongst ourselves. The rabbits had disappeared like magic. Surely the remedies we had taken would apply to Australia. As to the ferret, I was not at all satisfied with its action. It did not appear to have done nearly the good that I had anticipated. The cats were doing as much good, I thought. I placed as little reliance upon the ferret as I did upon poisoning or rabbit-fencing. The ferrets died off rapidly from distemper. They did not appear to at all increase in sufficient numbers to cope with the evil. Although a gill-ferret littered in large numbers, yet the young ones did not appear to survive. But they had done a certain amount of good. (Consequently I still advise their use. I would say this, however: that they must not be relied upon in the South Island for the high, snowy lands.)
I therefore determined to apply for the reward myself, and I sent one of the diseased rabbits to Sir James Hector to ask his opinion. That gentleman replied favourably. He had previously received two specimens of the disease from the Wairarapa, and he had himself seen a virulent disease of some kind amongst the rabbits in North America. Sir James had previously spoken to me about this disease that he had observed, and he therefore made up his mind definitely to identify it, upon receiving this third specimen from me, with the North American disease. Professor Thomas differs from this view, and says that the tape-worm is not the same—that it is totally distinct. It may be so, and Sir James Hector may be wrong. Our rabbit is not the same animal as the jack-rabbit of North America—a sort of hare; but, nevertheless, I wish to record my thorough appreciation of Sir James Hector's services in identifying the disease so far as he did. Sir James did not know which animal acted as host in passing the particular worm that is here. I said it was the dog. We had all along observed it coming from the dog. Neither Sir James nor Professor Thomas thought it could be the tame dog, although Professor Thomas was careful to express no decided opinion. It will be observed upon reference that Sir James Hector thought it came “probably from the wild dog and cat.” Of course we have wild dogs, and I had turned out many cats, which have thriven remarkably well; and these may have started the disease: but the tame dogs certainly do carry it on, and they will spread it readily in the South Island. The cats may also spread it, as there are at least a hundred cats upon my run now. The disease only requires to be started upon the runs in the south or elsewhere to perform as good work as it performed with us in the Wairarapa.
My letter to the Colonial Secretary of New South Wales, applying for the reward, found its way into the newspapers of
Australia, and immediately I was told by many of my fellow-settlers in the Wairarapa that the disease was no new thing; that some of them had observed it two, four, even six years ago; that they had it upon their runs, and other diseases as well, such as liver-rot, mange, scab, and lice. The generality of them said the disease (bladder-worm) was no good, and wondered at my taking any notice of the matter. Many of them, and the general number of the rabbit-men and Maoris, considered that the bladders were caused by gunshot wounds. Even the other day, when I was bringing a good specimen of the disease down to Sir James Hector, the Maoris clustering round the box remarked, “Ah! that rabbit was wounded.” All this evidence points to the one fact that for six years past this disease has been silently at work upon the runs in the Wairarapa, and to it may be attributed, just as much as to the winter poisoning or the ferrets, the further great fact that in the Wairarapa the rabbit-pest has been conquered. (I attribute the subjection of the pest to the three things acting in combination.) The mange, itch, or scab had also been observed upon my own and the neighbouring runs; but the rabbiters considered that such rabbits had been scorched or badly burnt in the many fires lit to clear off the scrub. Liver-rot had also been observed, especially upon Mr. Tully's run—a run celebrated for the bad state of the rabbit-pest there, but which I am happy to say is now almost clean. Professor Thomas's interim report does not say whether liver-rot is attributable to bladder-worm—or rabbit-fluke, as Sir James Hector named it: I fancy it is.
Now, let us leave detail and go into principles. Let us see what this bladder-worm really means. Let us take an atlas of the earth and inquire into the reasons why the four great continents of Europe, Asia, Africa, and America are free from the rabbit-pest, and why it is so bad in Australia and New Zealand. If my course of reasoning is found to be sound, then, surely, M. Pasteur's proposed mode of suppressing the difficulty with cholera-microbe solution will be found to be as absolutely useless as our winter poisoning, and very far indeed removed from the right method of cure. I use the words “absolutely useless” in this sense: that it will be no good M. Pasteur sweeping off the rabbits by millions if they breed up again, and have to be again swept off. Under the winter poisoning we are sweeping off the rabbits in New Zealand at the present moment at about fifty millions a year.
And, first, it will be remembered by members of this Institute that last year I read a paper upon “A Common Vital Force.” The reasoning in that paper has furnished me with matter for clearing up the present question. My argument is as follows—and Professor Thomas, before sending in his full
report, will do well to think over what I am about to say, and to amend his summary of conclusions at the end of his interim report lately presented to Parliament:—
The rabbit appears to have started in Africa. Negro legends all point to it as the cunning animal, just as our legends point to the fox. From Africa it passed to Asia and Europe, as European lands emerged from the sea. (I consider Africa the oldest continent, geologically, and the negroes the oldest race of men, ethnologically.) From Asia it passed into America, or the jack-rabbit there may have been in America coterminous with the rabbit's existence in Africa or Asia. With the rabbit went the stoat, weasel, ferret, cat, dog, fox, wolf, and other natural enemies. I am speaking now of many thousand years ago—long before men ever appeared upon the face of the earth, but still while the four present great continents were continents, and Australia and New Zealand isolated.
And these animals which we call the natural enemies were specially sent by nature to watch the rabbit and prey upon it, and prevent its excessive increase. Thus the common vital force always acts. One order of creation is not allowed to take possession of the earth—another checks it; and so the balance of utility is preserved.
Sir James Hector, thinking as I think, stated some months since that soon there would be no rabbits in New Zealand. I would point out to Sir James that in saying that he has gone too far. Nature checks excessive increase, it is true, but nature does not willingly allow any one order of creation to be exterminated. On many an estate at home there will still be found, after a thousand years of experience, the fox, the stoat, the weasel, the dog, the cat, and the rabbit side by side. Trap off the ground-vermin, as it is called, and the rabbit will rapidly increase; so that any idea of our depending entirely upon bladder-worm or any disease must be abandoned. The rabbit will never be exterminated now from the lands of Australasia. Nor is it advisable for us to exterminate it.
But there is a great distinction between the rabbit as an animal and the rabbit as a pest. Nature carefully makes this distinguishment in all living things. Only those things came to this planet of use to it, as its climatic conditions proved favourable to their reception, and each thing carried with it its own check from excessive increase. The general check (this course of reasoning supposes space to be filled with germs, and other planets inhabited) is a worm of some kind. For when any living thing becomes too thick—be it man, sheep, rabbit, pig, horse, ox, or other animal—immediately the land becomes infected by the excessive excreta of itself or its natural check. I rather fancy that its own excreta first starts
the check, which rapidly spreads by means of the host. In the sheep we see it when we say that the land becomes sheepsick. Upon such lands the hoggets get the lung-worm, and die off. So that, supposing we tried our best to keep but one animal running constantly upon one set of lands, the end would be that that animal would dwindle down to very few indeed. In the case of the rabbit its own intestinal worms or the intestinal worms of the natural enemy are always ready to infect the lands and guard those lands against entire occupation. And so determined is nature to do this that away up in the arctic regions, where the rabbit, jack-rabbit, and hare can go in comfort, being furred animals, there is it followed by the stoat changed into an ermine. The stoat puts on a warmer coat, and follows the rabbit even to the poles. For that reason stoats are alone to be relied upon by our Government here for suppressing the plague in the high snowy lands of the South Island.
Now let us look at the atlas, and see the position of Australia and New Zealand. What is it? Disconnection from the four great continents. Here there were neither rabbits nor any natural enemy (I allude to the end of the secondary period in geology, when Australia is supposed to have been separated from the mainland). The land was clean from either. Lately we have brought the rabbit, and, finding no check either against itself or against it as a pest, it rapidly developed into the pest form. Neither ferret, stoat, weasel, fox, nor wolf was here to infect the lands with the tape-worm eggs, and so the rabbit throve and multiplied. The dog alone was here, and in the Wairarapa the dog appears to have carried out nature's law of check. My accidentally giving the dogs areca-nut but assisted nature's law.
Of course, I do not say that the tape-worm I use is the worst form of tape-worm. There are two hundred and fifty different kinds of tape-worm, and I have no doubt that the tape-worm of the fox and wolf is a far more virulent disease than the tape-worm of the dog. But then I do not like to introduce such animals into Australasia, amongst our sheep. The Hon. Randall Johnson tells me that a proposition comes from Africa for us to use here the civet-cat and the meer-kat. (The civet-cat is closely allied to the aard-wolf.) But, again, I say that I do not like introducing here more ground-vermin than are absolutely necessary. I find that I have succeeded with the dog, cat, ferret, stoat, and weasel. What necessity is there to introduce anything further yet awhile? I feel almost sure that these animals will perform the work for Australasia. At any rate they should be tried before introducing any of the other animals. We never know how the feræ naturæ develope in these new lands. These require their
check just as much as the rabbit requires its check: hence my aversion to their introduction. Had the dog, cat, and ferret been capable of performing the work of suppression, I would never have introduced the stoat and the weasel into the Wairarapa. At any rate, if we have to concede to the full extent of the round of nature's law, let us wait until population becomes a little more dense with us, to impose the proper check of man.
From all this it will be seen how totally wide M. Pasteur is from the truth, and how little dependence can be placed upon purely scientific reasoning in dealing with this question.
That the rabbit multiplies itself rapidly upon insular lands of the globe is seen from two instances recorded in history. In A.D. 1 the inhabitants of the Balearic Isles petitioned the Roman Emperor Augustus for assistance in subduing a rabbit-pest there. Two legions of the Roman army were sent to get the plague down. It is evident now, from my course of reasoning, that these islands wanted the natural enemy.
Also, in the case of one of the Canary Islands, or Teneriffe. Prince Henry of Portugal, I think, sent some rabbits to one of them, and the inhabitants had very great difficulty in subduing the pest. I am a little uncertain as to the facts in this case, but I remember meeting with it some time since, accidentally, in the course of reading. This case, and the former one of the Balearic Isles, and New Zealand and Australia, are exactly alike. A narrow view of this question is therefore quite inadmissible. We can but look at it from the point of view I suggest—viz., with an atlas of the globe before us. Hitherto we have regarded the matter too narrowly in New Zealand, and M. Pasteur's remedy, strange to say, is too narrow also.
With regard to rabbit-fencing: I do not object to rabbit-fencing, but I consider it a waste of money. The best and most sure fence is the egg of the tape-worm upon the grass. The calculation for each dog is as follows: 1 × by 100 tape-worms, × by 100 segments, × by 1,000 ova.
As to the expense of the remedy, the beauty lies in its cheapness. Supposing the owner of each run in the South Island got but two of my diseased rabbits, and fed those rabbits to two hungry dogs in his pack, and then went, steadily hunting over his land, the moist lands would quickly become infected with the tape-worm eggs. The rabbits would eat them and get fluked, and soon the whole pack of dogs would be infected. The dogs would then infect the whole of the lands. Whether the ferrets, stoats, and weasels also carry the worm about I cannot say. I firmly believe they do; but I have all along been quite certain that the tame dog does so, and I think the cat also. Neither Sir James Hector nor
Professor Thomas is able to tell me anything about this; so I can but be guided by my practical experience. This is why I object to rabbit-fencing. I wish free, open fences for the dog and natural enemy to disseminate the tape-worm ova.
With regard to the danger of the sheep becoming fluked, I have never heard of a single case of the sort in the Wairarapa during the six years the disease has evidently been silently at work amongst the rabbits. Nor do I think that the bladder-worm of the rabbit can possibly infect the intestines of the sheep. Each order of nature has its own check. This can be seen from the fact that there are some two hundred and fifty different sorts of tape-worm. The rabbit might carry the proper sheep-fluke about in occasional instances, but I do not think that the sheep could possibly carry the rabbit-fluke about. At any rate, my sheep have been running upon my badly-infected rabbit-fluked lands, and no instance of death has yet occurred.
I need scarcely point out the severity of any tape-worm disease. A few years since seven hundred thousand pigs died near Chicago from trichinosis; last year a score of thousand hoggets died from lung-worm in the southern portion of this North Island of New Zealand; millions of sheep die in England from sheep-fluke. These are but instances of the severity of nature's laws. And nature's proper laws are continuous; not like M. Pasteur's remedy, or our own winter poisoning. How well do we know here that the rabbits grew proof against the poisoned grain, and refused to take it! So will the rabbits grow proof against cholera-microbes. Even a few fowls in each hen-roost always escape the ravages of chicken-cholera. Again, there were, and are still, many places in the South Island where we could not lay the poisoned grain. This escape from poison and disease, and these inaccessible places, yearly afford bases for the rabbits to breed up again. But there is no escape from bladder-worm or liver-rot.
With respect to the time the disease takes to effect the death of the rabbit, Professor Thomas mentions thirteen and twenty-one days after infection. We have always thought it took longer, but Professor Thomas thinks that he can make the disease even still more fatal. This is good news; but I do not think there is any necessity for it to be more fatal than it is. My run is clear now from the pest. I keep but one rabbiter and a pack of dogs over twelve thousand acres, and he catches about twenty-five rabbits a week. He could look after twenty thousand acres just as easily as twelve thousand. (I do not think his time thrown away in regularly going round the run. He saves his wages in other directions.) I am, however, indifferent what disease is selected, provided one of
nature's true remedies is applied. As to any disease like cholera suddenly sweeping off millions, I do not believe in its applicability to our present circumstances. Too much virulence would do harm.
In the use of so many dogs there is, of course, a danger of some dogs going wild. I should recommend the Government to publish the resolutions the settlers arrived at in my district, in 1884, upon this question. We are now through the rabbit-pest, and I do not think the wild dogs have killed a thousand sheep during the last four years over a million acres. Still, there are a few dogs gone wild in the bush, which we occasionally hear and see; but these can easily be got if the search for them is properly gone about. Prevention in this matter is better than cure. I prefer this danger to the introduction of the fox or wolf tribe.
There is some talk of this rabbit-disease attacking man in the form of hydatid. So it will. Hydatid from sheep attacks a few persons in Australia. Hydatid from the dog attacks a few of the Iceland people. I do not think much of these things. People cannot give up eating rabbit or mutton, or keeping dogs. To do that is the true remedy for the alarmists, and it is impracticable.
I would repeat that Professor Thomas does not draw the same conclusions from the mode of conquest of the pest in the Wairarapa that I draw. The winter poisoning had little or no effectuality. The ferrets worked well only in isolated places; in other places they would not live at all. But the three things acting in combination—viz., the poisoning, the natural enemy, and these diseases—effectually did the work of suppression. The poisoning swept off the millions; the ferret, cat, stoat, and weasel ate the young ones left; and then this bladder-worm and liver-rot attended upon all and completed the cure: but the poisoning itself was of little good. Herein it will be seen that practical experience is better than scientific conclusions. I hope Mr. Thomas, after reading this paper, will amend his interim report in the proper direction. It is not because the tape-worm here may not be exactly the same tape-worm that sweeps off the jack-rabbit in North America that Sir James Hector was wrong in the application of the general principle. That principle is that the excess of every order of life is held in check by some particular worm.
On the other hand, I must say that I saw far more from my ten years' practical experience in reducing the pest than Sir James Hector or Professor Thomas could tell me about it. Combining these things with M. Pasteur's proposals, I must be excused for doubting scientific conclusions. Sir James Hector proposes the introduction of the kit-fox here: I
think such a step would be wrong and unnecessary yet awhile. My opinion is that the wolf and fox tribes are the natural enemies of the sheep. We are clear of sheep-fluke now in Australasia, and I have no wish to introduce it. The bladder-worm hydatid of the rabbit, and sheep hydatid, are luckily two distinct things.
With respect to complete rabbit-extermination, I wish to say that it will be most inadvisable to attempt such a measure; and if it is attempted in Australia it will not succeed.
I am told that I am making too much of these diseases, and that specially favourable circumstances aided me in suppressing the pest in my own district. Those who say this do not see the importance of the principle contended for. So great is that principle that I have offered to reduce the rabbit-pest to a minimum in the South Island of this colony if I am allowed four years in which to do it. For that was the time it took me to reduce the pest in the South Wairarapa.