Characters, Hereditary and Acquired. 117 



parents, I am unable to affirm so important a con- 

 clusion on the basis supplied by these experiments. 



6th. Haematoma and dry gangrene of the ears in animals 

 born of parents in which these ear-alterations had been caused 

 by an injury to the restiform body. 



As regards the animals operated upon (i.e. the 

 parents), I find that the haematoma and dry gan- 

 grene may supervene either several weeks after the 

 operation, or at any subsequent time up to many 

 months. When it does supervene it usually affects 

 the upper parts of both ears, and may then eat its 

 way down until, in extreme cases, it has entirely 

 consumed two-thirds of the tissue of both ears. 

 As regards the progeny of animals thus affected, 

 in some cases, but by no means in all, a similarly 

 morbid state of the ears may arise apparently 

 at any time in the life-history of the individual. 

 But I have observed that in cases where two or 

 more individuals of the same litter develop this 

 diseased condition, they usually do so at about the 

 same time even though this be many months after 

 birth, and therefore after the animals are fully grown. 

 But in progeny the morbid process never goes so 

 far as in the parents which have been operated 

 upon, and it almost always affects the middle thirds 

 of the ears. In order to illustrate these points, repro- 

 ductions of two of my photographs are appended. 

 They represent the consequences of the operation on 

 a male and a female guinea-pig. Among the progeny 

 of both these animals there were several in which 

 a portion of each ear was consumed by apparently the 

 same process, where, of course, there had been no 

 operation. 



