RADIATE LAYER ROUND THE NUCLEUS 243 



will prove fruitful also for these questions, and that in fact 

 it may even be possible to obtain experimentally in oil- 

 foams many results explanatory of these matters. 



By the foregoing discussion I think I have explained 

 how the wide, in fact in all probability universal, occurrence 

 of the alveolar layer testifies entirely in favour of the foam 

 theory, since its origin can be explained by this theory, 

 while the framework theory gives us no help in under- 

 standing it. 



(/) Radiate. Layer of Alveoli round the Nucleus 



The case is just the same with the appearance of a 

 similar radiating layer round the nucleus. In the descrip- 

 tive part a series of examples were given of this. Heitz- 

 mann (1884) also everywhere figures very distinctly such a 

 radiate layer round the nucleus. I think, however, it may 

 be well assumed that it was constructed by him schematic- 

 ally rather than actually observed. Such a radiate arrange- 

 ment of the meshes round the nucleus was indicated by 

 Kupffer in 1870. Whether the clear area which Leydig 

 (1883) frequently observed round the nucleus, and which 

 was said to be traversed by radiating continuations of the 

 framework, represents in part at least this radiate layer, 

 seems to me doubtful ; at any rate it was then in most 

 cases considerably widened by shrinkage of the nucleus. 

 On the other hand, Kiinstler (1889) has represented the 

 radiate arrangement of the meshes towards the surface of 

 the nucleus in Gryptomonas perfectly well, and at the same 

 time was the first to observe that the outermost layer of 

 the much finer meshes within the nucleus itself is also 

 directed radially to its surface. In Chilomonas I have 

 also observed very plainly the radiate arrangement of the 

 protoplasmic meshes with regard to the nucleus. Now, this 

 phenomenon is again explained very simply on our concep- 

 tion of protoplasm. For the very form of the nucleus 

 shows at least in many cases that its surface at any rate 

 must be of firm consistence. 



Since it is not my intention to go here into the question 



