500 EEPOET OF THE BUEEATJ OF ANIMAL INDUSTKY. 



PREVENTIVE INOCULATION FOE PLEUEO-PNEUMONIA. 



The following letter, addressed to Dr. D. E. Salmon, Chief of the 

 Bureau of Animal Industry, by Dr. P. R. Gordon, chief inspector of 

 stock for Queensland, Australia, gives the results of the writer's ex- 

 periments in inoculation as a preventive of contagious pleuro-pneu- 

 monia or lung plague of cattle: 



OFFICE OF CHIEF INSPECTOR OF STOCK, 



Brisbane, Queensland, March 18, 1887. 



SIR: I have the honor to acknowledge, with thanks, the receipt of a copy of your 

 interesting and elaborate report No. 2, of the Bureau of Animal Industry, for the 

 year 1885. 



I may be permitted to offer a few remarks on that portion of your interesting re- 

 port on pleuro-pneumonia which refers more particularly, at page 138 et seq., to the 

 results of inoculation as a preventive in Australia, and in so doing I speak from an 

 official and practical experience on the subject of twenty-five years, nineteen of 

 which have been spent in my present office as chief inspector of live-stock for the 

 colony of Queensland. 



I do not take exception to the comments on the Blue Book and published returns 

 of New South Wales of 1875, because these returns were very incomplete, and at 

 that time opinions were divided on the subject, a considerable minority of cattle-own- 

 ers having been strongly under the influence of Professor Simmons' opinion, which 

 was largely circulated throughout the colonies. With an additional twelve years' 

 experience of the subject, however, I am safe in asserting that if the cattle-owners 

 of Australia of to-day were appealed to opinions would be all but unanimous in favor 

 of the practice. Such, at least, would be the verdict of my own colony, and no one 

 is in a better position than I am to judge of this matter. Inoculation had necessa- 

 rily to be carried out by non-professional men on most of the herds, and these pos- 

 sessed little knowledge as to the selection of proper virus. The cattle were wild, 

 few of them having ever been handled, except when being branded as calves, and 

 it will readily be understood that the operation was performed in crush-pens in 

 a very primitive manner. The difficulty in mustering wild herds rendered it im- 

 possible that every animal in a herd could be inoculated. On many herds the prac- 

 tice was not adopted at all, and as there were no restrictions on the traveling of in- 

 fected and diseased stock, the disease was kept constantly alive in the colonies. 



You are probably unaware that the whole of the cattle in the Australian continent, 

 numbering over seven and a half millions, may be said to compose one huge herd, 

 intermixing from one end of the colony to another, so that when a single case of 

 infection is introduced at one extreme end as was the case in 1858 it is only a 

 matter of time when it will be conveyed to the other extreme end of the Australian 

 continent. By the time the disease has spent itself in the south, it is in active opera- 

 tion in the herds of the north. As there is a constant traffic in store cattle from 

 the northern herds of Queensland to the southern colonies, infection is again intro- 

 duced to the southern herds, where it readily finds a nidus in the cattle that have 

 been born since the previous attack, and in this manner a constant wave of the dis- 

 ease is kept oscillating between the extreme north and south of the continent. 



There is much force in your argument that the reports and observations on the re- 

 sults of inoculation in Australia have been largely those of unscientific men, and as 

 such are not entitled to the same respect as those of qualified veterinary surgeons. 

 At the same time I may be permitted to remark that there are many duly qualified 

 veterinary surgeons in these colonies, who have had extensive experience in the 

 matter, and I think I am correct in saying they are unanimously in favor of the 

 practice. The government veterinarians of the whole group of Australian colonies 

 are decidedly favorable to it. 



But I think you will concede that on such a question (particularly when the opin- 

 ions of scientific men are fairly divided on it) the experiences and observations of 

 practical men may be allowed some weight, and I therefore take the liberty of 

 bringing under your notice the following facts : 



(1) In this colony we have an act providing for the registration of all brands and 

 ear marks in cattle, administered by me. Under that act a special ear mark is set 

 apart as an " inoculation ear mark " to distinguish cattle that have been inoculated, 

 and its use is not permitted for any other purpose, and it is an undoubted fact that 

 the losses among cattle bearing that ear mark are very few indeed, not exceeding 1 

 per cent, (including those which die from the result of the operation), whilst the 

 losses amongst uninoculated average from 5 and 10 to 15 and 20 per cent. 



