HEREDITY. 341 



parent and offspring resemble each other, because both 

 arise from tlie same Ivind of substance. 



It is well known that animals undergoing a metamor- 

 phosis pass through a series of stages, when tliey are prac- 

 tically different animals, with different surroundings and 

 food, these stages being transmitted from parent to oft'- 

 spring with wonderful certainty. This form of heredity 

 was called by Darwin '' inheritance at corresponding periods 

 of life," and by Haeckel " homochronous transmission." 



Both Lamarck and Darwin believed that characters 

 acquired during the lifetime of the parents may be and 

 often are transmitted to the offspring. If the characters 

 themselves do not appear, the tendency may, and tlie char- 

 acters croji out in a succeeding generation. This is disputed 

 by Weismann and other Neo-Darwinians, but upheld by 

 the Neo Lamarckians. There seem to occur at the present 

 day cases of such transmission, and in the early geological 

 times it was probably of frequent and normal occurrence. 

 Indeed, without it we find it difficult to explain homo- 

 chronous inheritance. 



LrrERATURB. 



A. Weismann: Essays upon Heredity (Oxford, 1889); The Germ 

 Plasm, a tlieory of heredity (New York, 189S). Also the wriliiigs 

 of Lamiirck, Darwiu, .Jaeger, Uibot, Spencer, lliieckel, Koelliker, 

 G-allou, Nilgeli, Maupas, Poullon, Hertwig, Buveri, aud others. 



