518 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1020. 



the differentiation of the somatic cells from the reproductive cells 

 among multicellular organisms. 



Herbert Spencer and the Lamarckians, believers in the heredity of 

 acquired characters, not being able to understand, for instance how 

 a termite soldier or an ant soldier being sterile is reproduced in the 

 following generation with a plasticity and with instincts which 

 appear to be neither male nor female, have supposed that the char- 

 acters peculiar to the neuters are nevertheless transmitted from gen- 

 eration to generation, owing to the fact that some neuters, even sol- 

 diers, are sometimes fertile. This opinion should be abandoned, 

 because the reproduction of neuters is exceptional and entirely insuffi- 

 cient, when not lacking entirely. We are, on the contrary, forced to 

 admit that the characters of the neuters are not due to the inheriting 

 of functions, but to the inherent properties of the egg of the species, 

 and this is of great importance. Establishing the comparison with 

 multicellular organisms, we have the right to ask ourselves whether 

 the heredity of acquired characters enters into their evolution, since 

 we must explain without this fact the sometimes considerable state 

 of perfection which the neuters show among the social insects. 



The naturalists who do not share the opinion of Herbert Spencer 

 are divided into two camps. Those of the first, with Emery, think 

 that the eggs from which the neuters come do not differ from the 

 eggs from which the fertile individuals are born, but that the germi- 

 native plasma of the eggs is labile, producing under the influence of 

 various conditions of nourishment different results; the neuters 

 would be trophogenic. 



The others, with Weismann, believe that the eggs giving birth to 

 the neuters contain a germinative plasma distinct from that con- 

 tained by the eggs from which come the normal individuals, and 

 that external conditions have no influence on the result ; the neuter 

 would be blastogenic. 



What do the facts tell us? Among the wasp Polistes gallicus, 

 among the most primitive of the Vespa, and among the humblebees 

 the workers differ from the fertilized female only in size; as the 

 year advances, as the society increases in number, as the conditions 

 of nourishment become more favorable, neuters are born whose size 

 is more and more developed, and there is scarcely any hiatus between 

 the smallest neuters which appear first and the perfect females. 

 Both represent the extreme fluctuations of the same type, between 

 which exist all transitions. With M. Paul Marchal we can believe 

 that it is the variable quantity of nourishment which determines 

 these differences, and in consequence that this category of neuters is 

 trophogenic. 



With M. Paul Marchal we can also believe that among the higher 

 types, as a result of a social perfection which accentuates the differ- 



