No. 59.3] 



SEX CONTROL IN PIGEONS 



403 



than in the second in all cases. If the results of my 800 

 analyses all ran as smoothly as do the 8 of this series there 

 would be no doubt of a perfect correlation of high mois- 

 ture values with small eggs, i. e., with male-producing eggs 

 —both small eggs of season, and small eggs of individual 

 clutches. But the results are not thus uniform and 

 smooth. There are some series which seem seriously to 

 depart from the order noted above. These can not be dis- 

 cussed here. We can, however, record our own belief that 

 the situation represented in the chart is, in the main, in- 

 dicated by the moisture determinations. 



Now the evidence that higher water values are asso- 

 ciated with male-producing eggs, lower water values with 

 female-producing eggs is of high importance in connec- 

 tion with our own generalization as to the basis of ger- 

 minal sex-difference; and is further of much interest as 

 being the means of demonstrating that in the— as I be- 

 lieve—several valid cases of sex-control now known, one 

 thing in common has really been effected, this though the 

 work has been carried out on a considerable variety of 

 animals, and though the procedures have themselves been 

 most various. The thing that seems to have been effected 

 in all cases has been the raising or lowering of the gen- 

 eral metabolism of the treated germs. If this conclusion 

 be definitely established biology may congratulate itself 

 that the further and complete analysis of this hereditary 

 character lies near at hand; is open to definite and easy 

 attack by methods already of demonstrated trustworth- 

 iness in this and other fields. And surely if such result 

 is possible it is timely, now when the "box within box" 

 revival has the sex character, like all others, dissociated 

 from all processes that can be studied or measured, and 

 associated with a particle so minute as hopelessly to defy 

 all direct and functional investigation. 



That higher water values in the tissues is associated 

 in development with increased metabolism is a fact well 

 established. We need cite here in reference to "tissue 

 growth and repair" only the well-known fact of the higher 

 water-content of embryonic tissues, and Minot's calcula- 



