I20 MARINE BIOLOGICAL LABORATORY. 



rest of the colony withers up and dies. Hence we find 

 in Volvox the first approach to a differentiation into 

 germ and somatic cells. 



Since Weismann made this startling assertion, that 

 death is not an attribute of all living organisms, much 

 opposing evidence has been brought forward. Most 

 prominent and recent among his opponents is E. Mau- 

 pas, of Algiers, who, after extensive study of some of 

 the Infusoria, asserts that degeneration and death occur 

 as normally among the Protozoa as among the Metazoa. 

 Before entering on his experiments, Maupas first deter- 

 mined very carefully the habits of the different species 

 which he chose for study. He found out the tempera- 

 ture to which they were best adapted, and the kind of 

 food on which they throve best. Then he took a single 

 individual, and isolated it on a glass slide, on which 

 it could be studied. This slide was kept over a dish 

 of water in a warm, damp chamber in which the air 

 was so thoroughly saturated with moisture that evapora- 

 tion was reduced to a minimum. Durins: its confine- 

 ment the animal was fed on its favorite food, and in 

 every particular what seemed to be the most suitable 

 conditions were maintained. He found that at the end 

 of seven days there were no less than 935 Infusoria in 

 his culture. One of these 935 he isolated and kept as 

 he had the first. In four days this single one had in- 

 creased to 230. One of these was isolated in the same 

 way, and this process of isolating and confining one 

 individual of each brood was continued throu2:h a larsre 

 number of generations. He shows the rapidity of in- 

 crease to be something almost incredible. Calculations 

 show that in six and a half days a single Stylonichia 



