282 PROTOPLASM 



for which reason the fibrillte must be the really active and 

 irritable components. This observation also seems con- 

 sistent with our view relative to the constitution of the 

 axis-cylinder, since the cross connections which we have 

 found are throughout discontinuous, and are therefore 

 essentially distinct from the longitudinally directed tracts of 

 the framework. Pfliiger further declares it to be unthink- 

 able that images of memory, such as we must ascribe to the 

 ganglion cells of the brain, could be retained by a fluid 

 substance such as the hyaloplasma ; rather that this would 

 only be possible in a solid substratum. So far as a concep- 

 tion of these things is generally possible in the present time, 

 his conclusion seems to me perfectly justified. Now, since 

 my interpretation of the structure of the ganglion cells 

 quite admits of their framework becoming partially or 

 entirely firm, it can be brought very well into harmony 

 with these physiological requirements. 



We have already learnt before that some investigators, 

 such as Brass (1883 and 1885), Schafer (1887), and Eohde 

 (1890 and 1891), have ranked themselves more or less 

 definitely on the side of Leydig's hypothesis. Schafer alone, 

 however, in more recent times has attempted to support the 

 opinion alleged by further investigations. In white blood 

 corpuscles of Amphibia, after fixing and staining, he believes 

 he has convinced himself that the pseudopodia are always 

 structureless and homogeneous, while the rest of the corpuscle, 

 appears more or less distinctly reticular. At the same time, 

 the homogeneous substance of the pseudopodia stains very 

 little or not at all, and is thus sharply marked off from the 

 strongly staining reticular substance of the rest of the 

 corpuscle. In these results Schafer sees, as has been said, 

 a decisive proof of the correctness of Leydig's hypothesis. 

 He also especially declares the derivation of the apparently 

 homogeneous protoplasm of pseudopodia, etc., from that of an 

 alveolar structure — an idea expressed by me in 1890, and 

 followed up more thoroughly in the present work — to be very 

 improbable and contrary to experience. Since the other 

 arguments, which are in opposition to the hypothesis of 

 Leydig and Schafer, are not touched upon at all in Schafer's 



