336 riddle: control of sex ratio 



low-storage capacity of the male-producing eggs as compared 

 with the high storage capacity of female producing eggs is there- 

 fore an index of higher oxidizing capacity or as more usually 

 stated, a higher metabolism of the male-producing eggs as com- 

 pared with the female-producing eggs. 



We may next examine the percentages of water in the eggs 

 of spring and autumn, and in the two eggs of the clutch. These 

 figures for one series of analyses are given along with other 

 analytical results in Table 7. They show a higher water con- 

 tent for the eggs of the spring (male-producers). Indeed, each 

 pair of eggs from the first of the season onward has a slightly 

 higher moisture value than the pair that follows it. The analyses 

 further show a higher percentage of water in the first egg of 

 the clutch, i.e., in the male-producer, than in the second or 

 female-producer in all cases. 



If the results of my nearly 900 analyses all ran as smoothly 

 as do the 8 of this series there would be no doubt of a perfect 

 correlation of high moisture values with small eggs, i.e., with 

 male-producing eggs — both small eggs of season, and small eggs 

 of individual clutches. The results throughout, however, are 

 not so uniform and smooth as here; there are some series which 

 seem seriously to depart from the order noted above. These 

 cannot be adequately discussed here. We can, however, record 

 our own belief that the situation represented in the table is, in 

 the main, indicated by the moisture determinations obtained 

 in the analyses of eggs produced by pure species. Two ad- 

 ditional methods of determining the amount of water in the 

 yolks, give a satisfactory confirmation of the conclusion that 

 the male-producing ovum contains a higher percentage of water 

 than does the female-producing ovum. 



It may be remarked at once that the two facts — a higher 

 metabolism, and a higher water value in the same egg (the 

 male-producing one) — are not to be regarded as a mere coinci- 

 dence. They are related facts, essentially correlated in that 

 the more hydrated state of these colloids, which contain only 

 54 to 59 per cent water, is certainly a more favorable state for 

 a higher rate of (oxidizing) metabolism than is the less hydrated 



