6o2 FOOT AND STROBELL. [Vol. XVI. 



proves to be the case, will this constituent produce a like effect 

 in combination with another fixative ? We hope by a careful 

 comparative study to be able to determine how much of the 

 structure seen in fixed cytoplasm is due to the fixation. 



The cytoplasm reacts very differently to different fixatives ; 

 for example, the spaces occupied by the hyalin globules ^ are 

 in some cases distinctly defined (photo. 17), while in others the 

 globules have apparently fused in all directions, producing a 

 scattering of the intermediary substance and consequent forma- 

 tion of rays. 



It is a significant fact that in those preparations where the 

 spherical spaces occupied by the hyalin globules are destroyed, 

 we usually find more definite rays, this being clearly shown by 

 comparing photo. 17 with photos. 15, 19, 21, and 22 (these five 

 photos, showing nearly the same stage of development of the 



The last four, with many of the chromo-acetic preparations 

 {e.g., 2, 8 and 9), might be called in evidence for the reticular 

 theory of cytoplasm, and photo. 17 supports with equal force 

 the alveolar theory. 



We are convinced that the indication of rays we have seen 

 in the living eggs is not comparable to the rays seen in prep- 

 arations where the hyalin globules have fused and scattered. 



Twelve fixatives are represented in our three plates, but we 

 do not wish to assert that any one of these preparations repre- 

 sents the typical effect of the special fixative, the reaction of 

 the ^%'g to any one fixative being very inconstant. This com- 

 plicates the problem and a comparative study can be profitably 

 carried out only by an exhaustive collection of photographs. 

 In the present paper attention will be called to a few suggestive 

 ■comparisons, awaiting further data before attempting to draw 

 definite conclusions. 



1 At Dr. Whitman's suggestion we have adopted the term hyalin globules to 

 designate the substance which in an earlier paper we called sap globules. This 

 substance, which is in globular form only at certain stages, we interpret as synon- 

 ymous with the hyaloplasm of some authors. We retain the term globule, 

 because when this substance is pressed out of the living egg, it keeps its globular 

 form, not fusing with water for several minutes. Treatment with osmic acid has 

 failed to demonstrate any fatty constituent. 



