i?8 PROTOPLASM 



objects seemed to him to be too much on the border-line 

 of visibility to obtain a definite decision. In any case, from 

 his numerous observations he was more inclined to the 

 assumption of a fibrillar structure, and also considered the 

 multiplicity of the structures too great to class them all 

 together under the conception of a continuous reticular 

 framework (p. 64), which seemed to him unproven and 

 improbable. That the so-called protoplasmic granules were 

 only the nodal points of a reticular framework hence seemed 

 to him in like manner not proved. On the other hand, 

 Flemming considered it certain that protoplasm shows 

 as a rule a filamentous structure, although the temporary 

 appearance of homogeneous protoplasm might be quite 

 possible. Such protoplasm would originate by " the filaments 

 . . . approaching until they came in contact, and perhaps 

 becoming fused for a time" (p. 66). The so-called inter- 

 vening matrix, or his " interfilar mass," he regards as possibly 

 fluid, but it might also possibly be " a yielding solid," since 

 after reagents it sometimes appeared finely granular. I 

 think, however, that the fine granulation of the so-called 

 interfilar mass was in most cases the actual fine reticular 

 structure, which he never definitely observed. 



It may, however, be asked how Flemming, so careful 

 an observer, and provided with the best apparatus, could 

 frequently declare that he was " never " able to convince 

 himself for certain of the reticular nature of protoplasm, 

 and hence felt doubtful about it. I think, ho.wever, that, 

 both from his chief work of 1880 and from his treatise of 

 the same period upon the structure of the cells of the spinal 

 ganglia, the conclusion may be drawn that Flemming reposed 

 rather too much confidence in certain apparatus that were 

 new at that time, namely, the Abbe's condenser. In both 

 memoirs passages can be found from which it is obvious 

 that Flemming as a rule conducted his investigations 

 with very " bright " light from the Abbe's condenser, and 

 without any diaphragm (see p. 43 ; spinal ganglion cells, 

 p. 15), and he cherishes the view that the images obtained 

 by such means quite determine the point. With " worse 

 light," however, he saw the reticular pattern of the 



