COHESION AND CRYSTALLIZATION 



33 



into segments. Finally the segmentation becomes complete, 

 and the preparation presents a muriform appearance, looking 

 in fact something like a mulberry (Fig. 24). If the prepara- 

 tion is preserved for several hours longer, we may see the 

 cells formed by segmentation unite around the circumference 

 so as to form a hollow bag corresponding to a gastrula, as 

 shown in Fig. 25. 



These preparations are extremely sensitive to external 



Fig. 24. — A circle of eight (hops 01 Indian ink 30 minutes after they have been 

 sown in a salt solution. The drops have undergone diffusion and sub- 

 sequent cohesion, resulting in a reticulate structure. 



influences, which renders the demonstration of cohesion 

 phenomena difficult. I have nevertheless on several occasions 

 been able to project the experiment on the screen during a 

 lecture. The segmentation is influenced by very slight 

 currents of diffusion, and I have many preparations showing 

 the segmentation regularly distributed in various ways along 

 radial diffusion lines. We may in this way produce many 

 varieties of structure lamellar, vacuolate, or cellular, in fact 



