IO4 MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



besides the concentration of the medium may influence the size 

 of the pseusopodia, for Goldschmidt (1915) states that the germ 

 cells form flagella in the cultures in hsemolymph and that these 

 flagella can be caused to appear and disappear by a change of 

 temperature. 



During mitosis the mitochondria become long, delicate threads 

 and lie around the spindle in such a way as to be easily mistaken 

 for the spindle (Figs. 14 and 22). In none of our preparations 

 were the spindle threads seen and the spindle itself did not show 

 as a cone of material, which had a different light refraction, as 

 it did in the chick. In one preparation the position of the spindle 

 at one pole was outlined (Fig. 16), but even in this case no 

 spindle threads were seen. 



The spindle is present however and can be readily shown by 

 means of acetic acid vapor, which destroys the mitochondria and 

 coagulates the cytoplasm sufficiently to show the spindle prac- 

 tically the same as it is shown in figures drawn from fixed material 

 (Figs. 21-26). 



Vital Stains. All stages in the development of the germ cell 

 were studied, not only by means of the living unstained cell, but 

 also by means of preparations stained with Janus green and 

 others stained with neutral red. A few preparations were 

 stained with both Janus green and neutral red. The Janus 

 green stain and also the neutral red stain were dissolved in the 

 culture medium in exceedingly dilute solutions, never more than 

 1-50,000 parts and frequently as dilute as 1-100,000 parts. 



The neutral red stains a large round granule, which is quite 

 different from the mitochondria, not only in size and appearance, 

 but also in behavior (Figs. I, 22, 36, 37, 39, 41, 46 and 49). This 

 granule has the same reaction to Brilliant cresylblue 2 b. as that 

 of the granule described by Lewis and Lewis ('15) in connection 

 with the "vacuole" and agrees in a few details with the "beta 

 globule" described by Coghill ('15). In a few cases the granule 

 reacts with the neutral red stain in the same manner as does the 

 neutral red granule, which Renaut, J. ('04) and Dubreuil, G. ('13) 

 describe in connection with the connective tissue development. 

 Owing to the fact that the literature does not furnish a satisfactory 

 term for this granule, it will be called simply the neutral red 

 granule in the following observations. Duesberg ('10) in certain 



