ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 535 



ments that the first organisms were non-nucleated Monera, that they 

 arose in the sea by a process of ionisation from a mixture of organic 

 and inorganic substances. The nucleated cell afterwards arose by the 

 symbiosis of two aniso-electrical non-nucleated cytodes. Everything 

 living has sex (negative and positive ions) and everything is living 

 because it has sex. 



Proportion of Sexes in Dogs.* — Walter Heape has investigated 

 this subject in an exhaustive manner, having dealt with a total of 

 36,867 pups, the data being obtained from the " Greyhound Stud Book," 

 the " Stock-keeper," " Kennel Register," etc. In interpreting the 

 evidence brought out in the statistics, the author indicates that he is 

 disposed to maintain: "(1) that through the medium of nutrition 

 supplied to the ovary, either by the quantity or by the quality of that 

 nutrition, either by its direct effect upon the ovarian ova or by its 

 indirect effect, a variation in the proportion of the sexes of the ova 

 produced, and therefore of the young born, is effected in all animals in 

 which the ripening of the ovarian ova is subject to selective action ; 

 (2) that when no selective action occurs in the ovary, the proportion 

 of the sexes of ovarian ova produced is governed by laws of heredity." 

 The sex is determined prior to or at the moment of fertilisation. 



Some of the facts made clear may now be given. Of the total 

 number of pups (36,867) the proportion of dogs per 100 bitches is 

 117 '49. Nearly 50 p.c. of these pups are greyhounds, with 118*5 dogs 

 per 100 bitches. Collies, with 6777 pups, give the nearest to these 

 proportions, viz., 118*19 dogs per 100 bitches. When the details of all 

 the large dogs are abstracted, the proportions yielded by the total 

 remaining breeds (11,846 pups) are 118" 04 dogs per 100 bitches. 

 Thus there is a very remarkable approximation in the proportion of the 

 sexes produced by greyhounds and collies, or by greyhounds and the 

 other large dogs taken as a whole. Terriers give the proportions of 

 114" 16 dogs per 100 bitches, a difference of about 4. This is not a 

 wide variation, yet the author thinks a more extensive series of data 

 would only serve to indicate a distinct racial variation in the proportion 

 of the sexes. Regarding greyhounds, during every month in a series of 

 years there is a preponderance of dog-pups born, but during October to 

 December, when the fewest pups are born, the proportion of dog-pups 

 is at its highest. The conclusion is drawn that conception during 

 August to November is specially favourable to the production of dog- 

 pups among greyhounds under the conditions of breeding now practised, 

 and this result is attributed to a selective action on the ova produced at 

 this time. The returns for collies show no evidence that conception at 

 any particular time of year affects the proportion of the sexes born. 

 The popular belief that there is a tendency to prolonged gestation when 

 the embryo is of the male sex is strongly supported by the returns of 

 breeders of bloodhounds and other large dogs, in which it is shown that 

 prolonged gestation is clearly associated with a greatly increased pro- 

 portion of male pups born. The size of the litter has apparently 

 nothing to do with the length of gestation. 



* Proc. Camb. Philos. Soc, xiv. (1907) pp. 121-51, 



