December 11, 1903.] 



SCIENCE. 



745 



below lot 7, which has had two famine years 

 in its ancestry succeeded bj' plenty daring 

 the current year. Lot 2 also ranks below 

 lot 6, a fact which appears strange, consid- 

 ering that lot 6 has sutfered two genera- 

 tion of famine, including the current year, 

 which is the only famine year experienced 

 by lot 2. In explanation of this anomalous 

 condition it is suggested that possiblj' the 

 larvffi of lot 6 were better fitted for en- 

 during and making the best of hard condi- 

 tions than were the individuals of lot 2, 

 the ancestors of the former lot having been 

 selected two years ago on a food-scarcity 

 basis. This suggestion gathers siipport from 

 an inspection of the mortality notes, from 

 which it appeal's that the number of deaths 

 — for which the famine was probably a con- 

 tributing 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 succes- 

 sive or alternate years. The figurss 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 generation which enjoyed an op- 

 timum amount of food having been grand- 

 parental, whereas the ancestors of all the 

 other lots except lot 8 have had the op- 

 timum amount of food during 1902 or 1903. 

 Lot 8 holds lowest rank, it and its ancestors 

 having been subject to trj'ing 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 lea.st the three 

 generations which .succeed it, yet the power 

 of recovery through generous feeding ex- 

 hibited by the progeny of individuals sub- 



jected to famine is so extensive (witness lot 

 5) that it appeai-s probable that every trace 

 left by the famine upon the race would 

 eventually disappear. It is even conceiv- 

 able 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. 



But although there is a large difference 

 between the well-fed and the poorly fed, 

 there persists, more obviously in late than 

 in early life, a very considerable discrep- 

 ancy as to size among the individuals of 

 each single lot whose environment, in so 

 far as food, temperature, room, humidity, 

 etc., constitute it, is identical 



For example, referring again to the 

 weights at spinning time of the larva? of 

 1903, it is true that although each lot has 

 a modal class of weights to which the ma- 

 jority of its individuals belong and about 

 which the rest of the lot distributes itself 

 rather symmetrically, the extremes are sur- 

 prisingly distant from one another. Thus 

 in lot 1 (the normal control lot) the ex- 

 tremes are 1,540 and 2,530 mg. ; in lot 2,* 

 800 and 1,402 mg.; in lot 3, 1.180 and 

 2,170 mg. ; in lot 4, 690 and 1,204 mg. : in 

 lot 5, 1,370 and 2,100 mg. 



That is to say, identical feeding has not 

 made identical full-grown larvje out of in- 

 dividuals which undoubtedly varied con- 

 (jcnitally at the start, those variations— in 

 embiyo — standing at birth in the same re- 

 lation to one another that they stand in 

 the adults, ha\nng merely been smaller 

 and less readily discernible in early life, 

 although manifestly present in delicately 

 measurable degree in the earliest records 

 nuide upcm normal individuals. For ex- 

 ample, weight mea.surements taken imme- 

 diately after the second moult range in 

 one lot from 21 to 39 mg., or 60 per 

 cent, of the modal weight, while the 

 weights in this same lot at spinning time, 



* See tablp, pajto "40, for tlic history of eaili lot. 



