RABBIT DESTRUCTION.

New Zealand Herald, Volume XLIV, Issue 13499, 28 May 1907, Page 6

RABBIT DESTRUCTION.

DR. danysz's . EXPERIMENTS,

"A WASTE OF TIME AND MONEY.''

"IN view of the published researches into the question by such men as M. Chamberland and;others, together with the poor results- of the Danysz experiments, .'it' seems to lis a waste of time and money for the latter to proceed further,". ;

That is the opinion formed by Dr. E. Angas Johnson and Mr. W. J. P. Giddiugs, editor of " Faulding's Medical Journal," the Commissioners appointed by the South Australian Government to report on the experiments conducted by Dr. Danysz on Broughton Island in the direction of the extermination Of rabbits through the medium of a contagious virus (says the Sydney Daily Telegraph of the _ 22nd inst.). ■ ;,■ ',-",'/.

; Tho Commissioners state that in view of the length of tame Dr.; Danysz's methods J took to kill rabbits, added to its uncertainty as compared with poisoning and trapping, they , thought its potency and its safety reI quired 4 much more satisfactory demonstration before, the question could bo ' said to have ..*'.'; been : adequately answered. Dr. Danysß admitted that microbes were living i creatures whose properties varied according to the conditions of time, temperature, and j Surroundings in which .'they -:we're, placed. jA? regarded Australia, "was familiar : only with the conditions'prevailing in the .Sydney ! Bofcid of Health laboratory and on BroughI ton,. Island, and haw could lie, therefore, I possibly ;:. .answer : for- 'tho"■'• action ■' of ': his microbe under, . say, the varying conditions to bo; met with in such widely differing localities ■ as Northern Queensland, •: Central Australia, aud Tasmania'.' ..Referring. to the experiments as recorded Iby Dr. ; Danysii;, the Commissioners state ithat an air of indifference to detail characterised, them, and consequently detracted j .from that scientific value whichshould attach to them. •; ■-'~ . .

Owing to the 'absence of lucidity in setting ; forth the total number of rabbits experimented with, the total which died, and the total which lived or were unaccounted for, : the ■ Commissioners state that they had had to make un those figures for themselves. , .It,was declared by Dr. Danysz, they point out, "that "in four ;experiments 72 rabbits, , infected with the virus, all died themselves, arid gave the : disease to 193 rabbits out of 307 'healthy rabbits, ■ with which they wore put; in other words, one rabbit infected, directly .with the virus has given a mortal disease to about three others (2.68 exactly)." For some : unexplained • reason Dr. Danysz omitted from his totals another experiment (No. 11), which, when counted in, absolutely destroyed his average. Taking the five (and not, four) experiments, the " Commissioners found that 412 rabbits were artificially infected .with the disease, and not 72,: as calculated by the doctor; arid that these 412 rabbits passed on the disease'; with fatal results to 141 other rabbits, and; not 193 as Dr. Danysz calculated. So that in lieu of one rabbit infected with the virus giving a mortal disease,to about three others, in reality it took three infected rabbits to impart the disease to one other. Experiment 11 showed that 320 tabbits were put in a paddock, and fed with lucerne contaminated .with the minced flesh of two rabbits, dead of infection, arid mixed with water. Ten days later, 20 infected rabbits were added to those already in the paddock During the \lO days the first batch of . 320 rabbits were fed on infected lucerne they should all have died, as, to use Dr. Danysz's own words: "It is possible to infect'rabbits by feeding them with the flesh of a rabbit dead with infection, minced, end mixed with water, and it is sufficient to put a drop of the virus in the eyes, on the nose, or on'the tongue of the animal'.to kill him ; With certainty." Some of this batch, were fed a second time on infected lucerne. There were thus two infections by feeding, and also the association with the 20 : directly-infected rabbits. The doctor declared ; that •'it takes about eight days to., kill all rabbits who have eaten virulent lucerne." ,i Yet the fact remained that one month ; after the first feeding, many of the rabbits were alive, arid' that nearly two months after their first infection, 32 live rabbits counted. • '111' conclusion, the ' Commissioners state that from what they "have learned of the experiments up to the present, they only say that they have not been impressed with their efficacy as a means of destroying the rabbit.;: The common methods of coping with the post by means of poison, trap-, an* wire-netting, seemed to bo more reliable than 'the- Danysz virus had proved itself to be "so far, at any rate. While the methods named presented no element of danger -to the; public health and welfare, they "could not say the same of anything in the nature of disease. -Whilst, so far as was known, hacmorrhagjc septicaemia had never communicated .itself to man, the same could not be said in regard to its treatment of domestic animals, upon which the prosperity of most countries depended.