Characters^ Hereditary and Acquired. 119 



It should be observed that not only is a different part 

 of the ear affected in the progeny, but also a very 

 much less quaniity thereof. Naturally, therefore, the 

 hypothesis of heredity seems less probable than that 

 of mere coincidence on the one hand, or of transmitted 

 microbes on the other. But I hope to have fairly 

 excluded both these alternative explanations. For, 

 as regards merely accidental coincidence, I have 

 never seen this very peculiar morbid process in the ears, 

 or in any other parts, of guinea-pigs which have 

 neither themselves had their restiform bodies in- 

 jured, nor been born of parents thus mutilated. As 

 regards the hypothesis of microbes, I have tried to 

 inoculate the corresponding parts of the ears of 

 normal guinea-pigs, by first scarifying those parts 

 and then rubbing them with the diseased surfaces of 

 the ears of mutilated guinea-pigs ; but have not been 

 able in this way to communicate the disease. 



It will be seen that the above results in large 

 measure corroborate the statements of Brown- 

 Sequard ; and it is only fair to add that he told me 

 they are the results which he had himself obtained 

 most frequently, but that he had al- ^ met with many 

 cases where the diseased condition of the ears in 

 parents affected the same parts in their progeny, and 

 also occurred in more equal degrees. Lastly, I should 

 like to remark, with regard to these experiments on 

 restifoim bodies, and for the benefit of any one else who 

 may hereafter repeat them, that it will be necessary 

 for him to obtain precise information touching the 

 modus operandi. For it is only one very localized 

 spot in each restiform body which has to be injured in 

 order to produce any of the results in question. 



