BUREAU OF ANIMAL INDUSTRY. StJl 



a destructive action upou the parasites. Tlio medicines thus introduced 

 bare a a opportunity of acting upon the parasites directly before they 

 arc all absorbed by the mucous membrane of the air-passages. There 

 is no reason to doubt that they may have even a secondary effect after 

 their absorption if they are naturally thrown off by the mucous mem- 

 brane of the air-passages and the epithelium of the alveoli, which is the 

 case with most volatile substances. 



The method of tracheal injections was first tried by Gohier in the 

 early i^art of the present century, after learning experimentally that 

 considerable quantities of liquid can be introduced into the trachea 

 without producing suffocation. Delafond some years after conducted 

 some experiments to determine the absorx)tive power of the air-iDassages. 

 He found that mucilaginous decoctions, solutions of sugar or honey, 

 are speedily absorbed when injected into the trachea, inducing slight 

 symptoms of suSbcation for one or two hours. He also found that solu- 

 tions of narcotic agents and stimulants manifest their physiological ef- 

 fects very soon after iujection, and that oils and oily medicines produce 

 a congestion of the lungs which is but slowly dissipated, and that even 

 very dilute solutions of mineral and vegetable acids produce inflamma- 

 tion, with copious secretion of mucus, giving rise to symptoms of as- 

 l)byxia and even leading to death. 



Dr. Levi, of the University of Pisa, has recently applied this method 

 in the treatment of a number of diseases {Manuel pratique des injections 

 traclieales dans le cheval, 18S3). His experiments also tended to show that 

 the mucous membrane absorbs very rapidly and is therefore less apt to 

 suffer from the injection of irritating substances than if the absorption 

 were less rapid. He also determined that the injection of small quanti- 

 ties of oily substances is not dangerous, the oil probably being emul- 

 sified and absorbed. Finally, there is always a slight reduction in the 

 number of respirations, amounting to about three or four per minute, 

 after the introduction of liquids, even when distilled water only is in- 

 jected. 



ATithout entering into interesting questions concerning the adminis- 

 tration of medicines in this manner in other diseases which are discussed 

 at length in the work mentioned, we find that the author has experi- 

 mented on but one case of lung- worms to test the efficacy of the method. 

 Others, however, have reported cases in which their success justifies a 

 detailed account of the method for future application. 



The instrument to be used is a simple hypodermic syringe (Plate VI, 

 pig. 7), holding from 1 to 2 fluid drachms. Tbe needle of the syringe 

 m.ist be provided with a removable solid rod or trocar, so as not to 

 become plugged when it is pushed through the skin and walls of the 

 trachea. As the needles are apt to break, a number of them should be 

 kei t on hand. After the operation the syringe should be carefully 

 wa:; led in pure water, the piston supplied with a drop of olive oil, and 

 the rocar replaced in the needle. 



It 's best to disinfect by filling the syringe and needle with a 5 per 

 cent, solution of carbolic acid, or a .1 per cent, solution of mercuric chlo- 

 ride' before washing in pure water. The disinfection, however, is not 

 absoi itely necessary in this operation if the syringe and needle be kept 

 thoro 'ghly clean. Fill the syringe and place aside. To introduce the 

 needl . extend the head of the animal so as to fix and make Diominent 



'The irmer is prepared l)y adding 5 parts by -n-eiglit of pure carbolic acid to 100 

 parts bj -weigbt of pure water previously heated; the latter by adding 1 part of tho 

 corrosive sublimate (a violent poison) to 1,000 parts of -water. 

 3Q AG '85 



