L86 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Unity of Meiotic Process in Plants and Animals.* — Victor flregoire 

 has made a critical comparative study of the results which have been 

 reached by observers of the maturation or meiotic process in plants and 

 animals. The general result is that lie is able to apply one scheme of 

 interpretation to a large number of cases in both kingdoms. Just as 

 there is a unity in the behaviour of the chromosomes in somatic karvo- 

 kinesis, so there is in the reduction division. The scheme followed is 

 described in somewhat forbidding terms as " une prereduction hetero- 

 homeotypique preparee par une pseudo-reduction prophasique par 

 parasyndese ou zygotenie." A large bibliography is appended. 



Abnormal Bone-growth in Absence of Functioning Testes.! — 

 A. C. Geddes believes that the immediate effects of removing functioning 

 gonads are (1) that the demands upon the internal food-supply of the 

 body are lessened ; and (2) that the body is deprived of some internal 

 secretion or nervous stimulus. The immediate effects are certainly 

 twofold : (1) the cells of the epiphysial cartilages are stimulated more 

 rapidly to proliferate ; and (2) there is an arrest in the development of 

 the penis, the scrotum, the prostate, the antrum of Highmore, and 

 possibly the brain. There is no evidence to show why the arrest in the 

 growth of these parts takes place. It may be supposed to be due to the 

 absence of a stimulus to growth conveyed by an internal secretion or 

 through the nervous system. However it be effected, it appears to 

 differ in origin altogether from the stimulus to growth experienced by 

 the epiphysial cartilages. The departures from the normal inter-relations 

 of the amount and rate of growth of the cartilages when the gonads are 

 removed or destroyed are not fortuitous, but follow the same regular 

 plan in men and animals. This plan is discussed at length. 



Influence of Malnutrition and Castration on Development of 

 Sheep's Skeleton.:}: — N. Tschirwinsky shows how malnutrition in youth 

 affects the development of the bones, sometimes retarding the rate of 

 growth without final effect ; sometimes lessening weight and size in 

 different parts proportionally, sometimes causing disproportionate growth ; 

 and so on. 



Castration of rams at the age of a month affects the form of the 

 skull, lengthens the neck, shortens and broadens the os innominatum, 

 lengthens long bones, inhibits the horns, greatly affects weight but in 

 different directions in different parts. 



Development of Rabbit's Teeth. § — J. Stach finds that the rudimen- 

 tary teeth discovered by Huxley in front of the incisors are really the 

 milk predecessors of the large incisors. 



Development of Vertebral Column in Reptiles and Birds. || — A. C. 

 Bruni has studied Gongylus ocellatus and the chick. It is shown in 

 detail that a vertebral body is formed from three components, (a) the 



* La Cellule, xxvi. (1910) pp. 223-422 (145 figs.). 



t Proc. R. Soc. Edinb., xxxi. (1910) pp. 100-150 (3 pis.). 



t Arch. Mikr. Anat. lxxv. (1910) pp. 522-61. 



§ Bull. Acad. Sci. Cracovie (1910) pp. 215-59 (2 pis.). 



|| Atti R. Accad. Sci. Torino, xlv. (1910) pp. 750-7 (1 pi.). 



