348 



ROBERT CHAMBERS. 



As regards longevity it will be seen that the immature egg de- 

 pends upon its nucleus (germinal vesicle) to prevent disintegra- 

 tion, for a fragment lacking the nucleus disintegrates very quickly. 

 On the other hand, the mature egg, which has become permeated 

 with the nuclear sap of the germinal vesicle, behaves quite diriei- 

 ently. The non-nucleated fragment of a mature egg lasts longer 

 than that of an immature egg and it is significant that the pres- 

 ence of the nucleus of the mature egg, which consists of not 

 much more than the chromosomal constituents, has no effect in 

 preventing disintegration. 



The long period that the endoplasmic sphere withstands disin- 

 tegration indicates that the factors which make for disintegra- 

 tion reside chiefly in the original cortex of the mature egg. 



In regard to fertilizability it is evident that the substance which 

 renders cytoplasm fertilizable emanates from the germinal ves- 

 icle and finally becomes localized in the cortex of the mature egg. 



We can, therefore, distinguish three factors in the starfish egg ; 

 one affecting longevity, the second affecting disintegration and 

 the third affecting fertilizability. The first and third have been 

 traced to the germinal vesicle of the immature egg. The second 

 is a function of the egg cortex. 



BIBLIOGRAPHY. 

 Barber, M. A. 



'14 The Pipette Method in the Isolation of Single Micro-organisms and 

 in the Inoculation of Substances into Living Cells. Philipp. Jour. Sc., 

 IX., Sec. B, 307. 

 Buller, A. H. R. 



'02 Is Chemotaxis a Factor in the Fertilization of Animals? Quar. Jour. 



Micr. Sc., XIV., 145. 

 Chambers, Robert 



'15 Microdissection Studies on the Physical Properties of Protoplasm. 

 Lancet-Clinic, Mar. 27. 



