MODERNBIOLOGY 4x5 



of the Amphioxus. In his later years, an ophthalmic disease having put an 

 end to his microscopical work, he entered upon a new field of research, in 

 which he undoubtedly carried out the most important work of his life — 

 namely, comparative anthropology. Till then this science had followed the 

 lines of Blumenbach; mankind had been divided into races for the most part 

 according to the colour of the skin. Retzius began to take an interest in 

 the discovery of human remains in the prehistoric graves of Scandinavia, 

 and in the course of his investigations found considerable variation in the 

 shape of the brain-cap. He extended these researches to include other human 

 races and thereupon found that the skulls may be divided, according to the 

 proportion between length and breadth, into long and short skulls — doli- 

 chocephalic and brachycephalic — and, further, after the shape of the facial 

 bones, into orthognathic and prognathic. Several peoples externally akin 

 were found to differ in these respects — • thus, for instance, the Germanic 

 are long-skulled, the Slav short-skulled — and as a result of this idea there 

 was created a field of human research based on true comparative anatomy, 

 which was afterwards followed up with splendid results by other investi- 

 gators: Virchow, Broca, the younger Retzius, and many others. 



In France during this period marine biology made rapid progress and 

 contributed much of importance to the general development of our knowl- 

 edge in this sphere; of the students who distinguished themselves here, two 

 are especially worthy of mention. Henri Milne-Edwards (1800-85) ^^^ 

 a native of Belgium, but of English descent. He came early to Paris and even- 

 tually worked as a professor there. Having been a pupil of Cuvier's, he car- 

 ried on with distinction the latter's work in the sphere of invertebrate 

 research. When quite a young man he published an extremely useful work, 

 a comparative study of the vascular and nervous systems of the Crustacea; 

 after that followed an extensive work on the fauna of the French coast, 

 in which the Annelida in particular were described with minute care. A 

 masterpiece of its kind is his Histoin naturelle des crustacees, wherein this 

 order is treated with thoroughness and perspicacity, and a system, based on 

 comparative anatomy, is worked out which is largely applied even today. 

 Further we may mention his work on the coral animals and his study of 

 the evolution of the ascidians, as well as a large number of deep-sea investi- 

 gations. 



Another who worked along the same lines was Felix Joseph Henri 

 Lacaze-Duthiers (182.1-1901). Born in the south of France of a distinguished 

 family, he devoted himself to the study of medicine and became a professor, 

 first of all at Lille and then in Paris. His numerous works deal chiefly with 

 the MoUusca, the anatomy and evolution of which he worked out in detail; 

 amongst other things he worked out the anatomy of the purpura and its 

 colour-secretion, which was known to the ancients, but had since been 



