144 HEREDITARY CHARACTERS 



various nerves, also suffered from epileptic fits. In some 

 other guinea-pigs, in which a large nerve in the hind limb 

 (sciatic) had been divided, the animals gnawed off two or 

 three toes, which had been rendered insensitive by the 

 operation. In some of the offspring of these guinea-pigs 

 two or three toes were absent. The results obtained by 

 Brown-Sequard himself were partially confirmed by some 

 of the assistants in his laboratory during the same period. 

 When, however, Sommer repeated several of these experi- 

 ments he obtained quite different results. 1 He did similar 

 operations upon similar nerves, arid produced epileptic fits 

 in the animals he operated upon, but in no case did epilepsy 

 or any other defect such as those described by Brown- 

 Sequard and his assistants, appear in the offspring of these 

 guinea-pigs. Certain remarks made by Professor T. H. 

 Morgan are very suggestive with regard to some of the 

 results in these experiments. 2 " While carrying out some 

 experiments in telegony with mice, I found in one litter of 

 mice that when the young came out of the nest they were 

 tail-less. The same thing happened again when the second 

 litter was produced, but this time I made my observations 

 sooner, and examined the young mice immediately after 

 birth. I found that the mother had bitten off, and pre- 

 sumably eaten, the tails of her offspring at the time of 

 birth. Had I been carrying on a series of experiments to 

 see if, when the tails of the parents were cut off, the young 

 inherited the defect, I might have been led into the error 

 of supposing that I had found such a case in these mice. 

 If this idiosyncrasy of the mother had reappeared in any 

 of her descendants, the tails might have disappeared in 

 succeeding generations. This perversion of the maternal 

 instincts is not difficult to understand, when we recall that 

 the female mouse bites off the navel-string of each of her 



1 Sommer, Max, "Die Brown-Sequard'sche Meerschweinschenepilepsie und 

 ihre erbliche Uebertragung auf die Nachkommen," Aus der psychiatrischcn 

 Klinik der Universitat Jena, 1900. 



2 Morgan, T. H., Evolution and Adaptation, New York, Macmillan Co., 

 1903. 



