THE PKOVISIONAL HYPOTHESIS OF PAXEGENESI3. 307 



But the evidence which admits of no douht is that given 

 by Brown-Sequard with respect to Guinea-pigs, which, 

 after their sciatic nerves had been divided, gnawed off 

 their own gangrenous toes, and the toes of their offspring 

 were deficient in at least thirteen instances on the corre- 

 sponding feet. The inheritance of the lost part in several 

 of these cases is all the more remarkable as only one 

 parent was affected ; but we know that a congenital de- 

 ficiency is often transmitted from one parent alone — for 

 instance, the offspring of hornless cattle of either sex, 

 when crossed with perfect animals, are often hornless. 

 How, then, in accordance with our hypothesis can we ac- 

 count for mutilations being sometimes strongly inherited, 

 if they are followed by diseased action ? The answer 

 probably is that all the gemmules of the mutilated or 

 amputated part are gradually attracted to the diseased 

 surface during the reparative process, and are there de- 

 stroyed by the morbid action. 



TRANSMISSION LIMITED. 



Pa^e 396 ^^ e transmission of dormant gemmules 



during many successive generations is hardly 

 in itself more improbable, as previously remarked, than 

 the retention during many ages of rudimentary organs, 

 or even only of a tendency to the production of a rudi- 

 ment ; but there is no reason to suppose that dormant 

 gemmules can be transmitted and propagated forever. 

 Excessively minute and numerous as they are believed to 

 be, an infinite number, derived, during a long course of 

 modification and descent, from each unit of each progeni- 

 tor, could not be supported or nourished by the organism. 

 But it does not seem improbable that certain gemmules, 

 under favorable conditions, should be retained and go 



