SUMMARY OF CURRENT RESEARCHES 



RHXATING TO 



ZOOLOGY AND BOTANY 



(PRINCIPALLY invertebrata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryology. t 



Fertility and Hatching of Eggs.}— R. Pearl and F. M. Surface 

 publish the results of their study of the factors which influence the 

 hatching of eggs. There is a small but still sensible correlation 

 between the fertility and the hatching quality of eggs. In general, or 

 on an average, the hens whose eggs run high in fertility will also tend 

 to show a high hatching quality of eggs (percentage of fertile eggs 

 hatched), and vice versa. Conditions of housing have a marked and 

 definite influence on the mean fertility and hatching quality of eggs. 

 It was found that both the fertility and hatching quality of eggs were 

 very much better in a " curtain-front " house, which furnished an 

 abundance of fresh, pure air, than when use was made of what was 

 formerly thought to be a highly desirable type of heated house, without 

 curtain-front, but with a supposed adequate system of indirect venti- 

 lation. The hatching quality of eggs is generally less variable in 

 proportion to the mean of the character varying than is fertility. The 

 variability in regard to both fertility and to hatching quality is markedly 

 influenced by environmental conditions. The data obtained show that 

 the individuality of the female bird is a very important factor in the 

 determination of the fertility of the eggs. Different individual females 

 have characteristic degrees of fertility of their eggs, independent 

 (within limits) of the character of the male bird with which they are 

 mated. The statistics also indicate that there is no relation whatever 

 between winter egg-production and the percentage of fertile eggs pro- 

 duced throughout the season. But there is a distinct correlation 

 between winter laying and the percentage of fertile eggs hatched during 



* The Society are not intended to be denoted by the editorial " we," and tbey 

 do not bold themselves responsible for the views of the authors of the papers 

 noted, nor for any claim to novelty or otherwise made by them. The object of 

 this part of the Journal is to present a summary of the papers as actually pub- 

 lished, and to describe and illustrate Instruments, Apparatus, etc., which are 

 either new or have not been previously described in this country. 



f This section includes not only papers relating to Embryology properly so 

 called, but also those dealing with Evolution, Development, Reproduction, and 

 allied subjects. 



X Bull. Maine Agric. Exper. Station, No. 168 (1909) pp. 105-64 (15 figs.) 



2 P 2 



