34 ^^^^m PROTECTION OF PLANTS. 1917-18 



(3) Extraction of grubs from the back. 



The methods recommended here have been tested time and again all over the 

 country. Osborn^^ (p. 94) advises coating the backs of animals from neck to loins 

 with tar, or with a mixture composed of sulphur, 4 ounces; spirits of tar, 1 gill; 

 whale oil, 1 quart; this preparation to be applied once a week. This measure is 

 unfortunately not practicable among the large herds on big ranches. 



The application of kerosene to the eggs before they hatch will kill the grubs 

 inside. This is also a rather tedious process. 



From January onward the grubs appear on the back, and measures should 

 be promptly adopted to squeeze them from the tumors. After the bots have 

 been removed, the tumors should be dressed a few times with vaseline in which 

 carbolic acid has been mixed, or with some other healing antiseptic ointment. In 

 order that the full benefit of such a measure as this might be derived, it would 

 be necessary that co-operative efforts should be adopted throughout the country. 

 Nevertheless, individual stock owners who adopt this measure would find that 

 they would secure practical immunity in their own herds, since the fly travels only 

 short distances. 



It is sometimes advocated that the grubs be killed inside the tumors by the 

 application of kerosene or mercurial ointment, but it will be readily understood 

 how the absorption of the resulting putrefying products of the dead grub would be 

 deleterious to the systemic functions of the host. The non-absorption of the 

 chitinous cuticle, however, may be the cause of a persistent abscess. 



In districts where arsenicals or crude petroleum dips are regularly applied to 

 cattle to combat infestations of ticks, it has been found that the animals are, to 

 some extent, also protected against the attacks of warble-flies as well as blood- 

 sucking flies. 



Anaphylaxis and Warbles. 



The term anaphylaxis is used in medical and veterinary science to designate 

 these reactions which follow the injection of foreign albuminous substances, not 

 in themselves toxic, into an animal which has previously been rendered sensitive 

 by a previous injection of the same substances. The symptoms, under certain 

 conditions, may be markedly toxic or even fatal. 



The conditions necessary to the production of anaphylactic shock may already 

 exist naturally in an animal infested by parasites or which has been infested by 

 parasites and the characteristic symptoms, as shown by Hadwen and Bruce^ 

 may readily develop in such cases where the extracted body-juices of the specific 

 parasite are re-injected into the particular host. This not only applies to warbles 



