APPENDIX 8l 



deaths — for which the famine was probably a contributing and not a primary 

 cause — in each lot which is for the first time subjected to short rations is almost 

 doubly greater than the number of deaths in lots which are descended from 

 starved ancestors, whether these ancestral famines occurred in successive or 

 alternate years. The figures indicate that a reduction of food is almost twice 

 as destructive upon the first generation which is subjected to it as it is when 

 visited on a second generation. Lot 4 follows lot 2 as the seventh in rank 

 and its position is in accord with the rule above noted, its latest ancestral gene- 

 ration which enjoyed an optimum amount of food having been grand-parental, 

 whereas the ancestors of all the other lots except lot 8 have had the optimum 

 amount of food during 1902 or 1903. Lot 8 holds lowest rank, it and its 

 ancestors having been subject to trying conditions throughout the entire three 

 years, during some one or two of which all the other lots have enjoyed the 

 best of food conditions. Thus it appears that a generation of famine leaves its 

 impression upon at least the three generations which succeed it, yet the power of 

 recovery through generous feeding exhibited by the progeny of individuals 

 subjected to famine is so extensive (witness lot 5) that it appears probable that 

 every trace left by the famine upon the race would eventually disappear. It is 

 even conceivable that the ultimate result of the famine would be a strengthening 

 of the race, the famine having acted the part of a selective agent, preserving 

 only the strong. 



That conditions of alimentation bear a directive relation to functional 

 activity may be demonstrated by reference to the records of the physiological 

 functions of moulting, spinning, pupating and emerging, of the individuals of 

 the experimental lots. 



An abnormal extension of the time needed for the metamorphosis follows 

 upon a reduction of the food supply. The degree of extension depends with the 

 utmost nicety upon the amount of food given the larvje. For example, among 

 the 1901 generation of silkworms, one control lot of twenty larvae was given 

 •the optimum amount of food, a second lot of twenty larvae one-half 

 this amount, and a third lot of twenty larvae one-quarter of the amount. To 

 take the time of the fourth moulting as an illustration, the moulting was begun 

 by the first lot, which led the way by two and a half days, at the end of which 

 the second lot began to moult, while the third lot was twenty-four hours behind 

 the second. All the individuals of the first lot had finished moulting on April 20, 

 all of the second on April 24, while the moulting in the third lot continued 

 until April 29. 



As in the matter of weight, this retarding of the functions, by means of a 

 reduced food supply, affects not only the immediate generation which is sub- 

 jected to the famine, but the lingering effects of it may be traced in the progeny 

 of the dwarfed individuals at least unto the third generation, even though two 

 years of plenty follow the one year of famine. The conditions which obtain in 

 each lot of individuals of the 1903 generation at spinning time are shown in the 

 following table, which is based upon polygons erected to include all the 

 individuals in each lot. 



