198 PROTOPLASM 



invisible, as has already been thoroughly discussed above 

 (p. 179). If we examine one of Altmann's- figures, as, for 

 example, the pigment cell depicted on Plate I. (1890), 

 which is supposed to represent to a certain extent the 

 typical structure of the cell, the remarks just made will 

 become still more obvious. We miss throughout this figure 

 any distinct limiting contour to the cell. Frequently little 

 aggregations or strands of pigment granules may be noted, 

 which lie entirely isolated, without any connection with the 

 rest of the cell. Hence it may be inferred very definitely, 

 that Altmann has in reality only observed the granules, 

 and has overlooked, on the other hand, the protoplasmic 

 framework. 



A similar result is obtained, moreover, if we pay atten- 

 tion more especially to the alleged formation of fibrils by 

 arrangement of the granules in rows. In most of the figures 

 it can be plainly made out that the fibrils do not consist at 

 all of closely packed granules, but that clear spaces intervene 

 between the granules. Only in very few cases relatively are 

 the fibrillee drawn as continuous red lines, which lie rather 

 scattered in the cell. I put aside the latter cases, with 

 regard to which I will assume that the continuous fibrils 

 would prove to consist of granules when more closely 

 studied, and will linger for a moment over the more 

 freq^uent instances of the kind first mentioned. In my 

 opinion, these observations are in favour of just the very 

 thing which Altmann wishes to deny, namely, that some- 

 thing must be present which maintains the rows of granules 

 in their arrangement; in favour, that is to say, of the 

 presence of a fibril distinct from the granules, or rather 

 of a fibril-like tract of the meshwork of the protoplasmic 

 framework. 



For the reasons enumerated I must conclude that Alt- 

 mann's objections to a reticular framework of protoplasm are 

 futile. 



Although it lies beyond the scope of the task we have 

 undertaken to examine more closely the importance which 

 Altmann ascribes to the granules, yet I must not pass this 

 over altogether, since a few critical remarks on this point 



