LIVING SUBSTANCE 



87 



scarcely be distinguished from the latter. From the accompany- 

 ing figures (Fig. 29, a and h), which are taken from Blitschli, the 

 identity in structure of the two objects may be recognised at a 

 glance. After the very careful and comprehensive investigations, 

 the results of which Blitschli has published in his book, doubt can 

 no longer exist that the problematic fine structure of protoplasm 

 is_ in reality foam-structure, which depends upon the presence 

 within a uniform ground- mass of a large number of extremely fine 



Fig. 29. — a, Foam-structure in the inti-acapsular protoplasm of Thalassicolla nvxleata. b, Foam 

 from olive oil and cane-sugar, c, Protoplasmic structure in a pseudopodial extension of a 

 foraminifer-cell (Miliola)^ d, Protoplasmic structure of an epidermis-cell of an earthworm, 

 (After Blitschli.) 



vacuoles, lying almost at the limit of microscopic visibility, and so 

 close together that their walls consist of relatively thin lamellae. 

 Further, Butschli has demonstrated this foam-structure in so 

 many wholly different forms of cells (Fig. 29, «, c, d) that its wide 

 distribution can be disputed no longer. 



As the result of these recent investigations the following picture 

 can be formed of the finer morphological structure of protoplasm. 

 Protoplasm consists of a ground -mass, in many cases completely 

 homogeneous, in most cases very finely foam-like or honey-comb- 

 like, in which lies embedded a greater or less quantity of very 



