6 E. J. LUND 



which is under many conditions a typical reaction — and if the latter 

 were the case, to what extent it had proceeded. Death was taken to 

 have occurred when the cell had ceased to move and began to disinte- 

 grate. In this way a record of the effects of the food on the maintenance 

 of form, degree of activity and length of life, was obtained, so that from 

 these the means can be taken and compared. 



To save space, instead of giving the detailed results in the 

 form of tables they are given by curves and averages. Curves 

 A, B and C of figure 1 represent for the three sets respectively, 

 the longevity or death rate. Points on the abscissa indicate the 

 time in hours, while points on the ordinate represent the number 

 of individuals which were still alive at the time the record was 

 taken. 



The curves A and B of Sets A and B respectively, show clearly 

 (1) that the yolk and vitellin had a definite effect in prolonging 

 the life of the cell. The relation of curves A and B to each other 

 will become clearer when we have considered later experiments 

 (p. 28) which show, other things being equal, that we should 

 expect longer life from individuals fed both lipoids and protein. 

 By comparing the average length of life in the three sets we find 

 that Set A lived 4.98, Set B, 5.39 and Set C 3.20 days. Sets A 

 and B, therefore, lived on the average about two days longer than 

 the unfed Set C. (2) The vitellin grains underwent total di- 

 gestion and resorption in most cases, while the fresh yolk grains 

 were generally only partially digested, this was especially the 

 case where more than 2 or 3 grains were eaten. (3) The animals 

 which had been fed were on the average more vigorous than 

 those of Set C. (4) The animals of Set A grew to be larger in 

 most cases than those of either Set B, or Set C. Many of Set 

 A became twice as large as those of Set C, while those fed vitellin 

 were on the average larger than any of Set C. The maximum 

 size was reached about thirty-six hours after feeding. 



There can therefore be no question but that both the fresh 

 yolk and the vitellin entered into the chain of metabolic proc- 

 esses and were in part at least, drawn upon by the cell for its 

 energy requirement. But very few of the organisms divided. 

 "Whether yolk or vitellin is a sufficient diet for cell division as 



