CRITICISM OF LEYDIG AND SCHAFER 



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dissertation, I need merely confine myself here to a brief 

 discussion of the objections set forth above. My view, that 

 the alveolar structure is not wanting even in apparently 

 homogeneous protoplasm, but is only no longer traceable 

 owing to the fineness of the walls of the alveoli, is held by 

 Schafer, as has been remarked, to be contradicted by the 

 alleged sharply -defined limit between the reticular and 

 the homogeneous protoplasm. With regard to this point I 

 may simply refer to the investigations upon the apparently 

 homogeneous pseudopodia of Amcebcc and of Gromia Dujardini 

 which are described in an earlier part of this work. More- 

 over, I may lay especial stress on the fact that, in the 

 pseudopodia investigated by me, I never observed a snarp 

 boundary between the reticular and the apparently homo- 

 geneous protoplasm, but could always see a transitional zone 

 both in life and in preparations. In fact, it may frequently 

 be observed in the pseudopodia, that the structure becomes 

 fainter at the extremity, or even becomes indistinct before 

 reaching the extremity, which causes the latter to appear 

 homogeneous. I do not believe, moreover, that the pseudo- 

 podia of the blood corpuscles investigated by Schafer behave 

 differently in this respect ; on the contrary, even in Schafer's 

 Fig. 4 (1891, 1893), it can be seen in many places that the 

 reticular structure gradually becomes blurred towards the 

 lobed or rim-like pseudopodia, and insensibly passes into them. 

 If in other places a very sharp limit seems to exist between 

 the homogeneous protoplasm and the reticular central 

 portion of the corpuscle, this can be explained by circum- 

 stances of another kind. Schafer specially mentions that 

 the homogeneous substance of the pseudopodia, which in 

 accordance with his view he regards as enchylema (hyalo- 

 plasm) which has crept or flowed out, stains much more 

 feebly than the granular reticular central protoplasm, and 

 that therefore the two must also differ chemically, i.e. that 

 the strongly staining spongioplasmic framework can only be 

 present in the reticular portion. Now we have frequently 

 found that the spongioplasmic framework, i.e. the framework 

 substance of the alveolar protoplasm, stains, as a rule, very 

 feebly, and that the apparently intense coloration of it, 



