SUBCUTANEOUS INOCULATION OF ANIMALS 229 



edges of the wound drawn evenly and gently together by 

 tying the sutures, and the lines of incision dressed with 

 collodion. It should be needless to say that this operation 

 must be conducted under the strictest precautions, to 

 avoid complications. All instruments, sutures, ligatures, 

 etc., must be carefully sterilized either in the steam sterilizer 

 for twenty minutes, or by boiling in 2 per cent, sodium 

 carbonate solution for ten minutes; the hands of the opera- 

 tor, though they should not touch the wound, must be 

 carefully cleansed, and the material to be introduced into 

 the abdomen should be handled with only sterilized instru- 

 ments. 



Inoculation into the pleural cavity is much less frequently 

 required — in fact, it is not a routine method. It is not easy 

 to enter the pleural cavity with a hypodermic needle without 

 injuring the lung, and it is rare that conditions call for the 

 introduction of solid particles into this locality. 



Inoculation into the anterior chamber of the eye is per- 

 formed by making a puncture through the cornea just in 

 front of its junction with the sclerotic, the knife being 

 passed into the anterior chamber in a plane parallel to the 

 plane of the iris. By the aid of a fine pair of forceps the bit 

 of tissue is passed through the opening thus made and is 

 deposited upon the iris, where it is allowed to remain, and 

 where its pathogenic activities upon the iris can be con- 

 veniently studied. It is a mode of inoculation of very 

 limited application, and is therefore but rarely practised. 

 It was employed in the classical experiments of Cohnheim 

 in demonstrating the infectious nature of tuberculous tissues, 

 tuberculosis of the iris being the constant result of the 

 introduction of tuberculous tissue into the anterior chamber 

 of the eye of rabbits. 



