HIS OBJECTIONS TO A FRAMEWORK 197 



In 1890, finally, he retains only the fibrils, while the 

 networks are attributed to erroneous observations. The 

 apparent reticular structure is explained as a delusive 

 appearance depending on the fact that the closely packed 

 unstained granules have been overlooked, and have been 

 interpreted as the spaces of a meshwork. I think I need 

 only say a little here concerning this view. Altmann 

 extends it in like manner to the nuclei, the structure of 

 which is supposed to correspond exactly to that of the 

 protoplasm. The reticular framework of the nucleus is also, 

 according to his idea, a deception. But any one who has 

 seen the granules of the nucleus and of the protoplasm in 

 the unstained condition, when they are, of course, just as 

 visible as when stained, knows that they are denser and 

 darker structures, with a high power of refraction, which, 

 therefore, could not be confused with the clear meshes of the 

 protoplasmic network by any observer at all experienced. 

 On the other hand, in the investigations set forth above, we 

 have come across granules sufficiently often, and have always 

 found that they lie in the framework of the protoplasm. 

 In staining experiments with very various aniline colours, 

 etc., it was always shown in the plainest manner that the 

 meshes of the network remain colourless, while the proto- 

 plasmic framework assumes only a feeble coloration. It is 

 the granules alone which stain intensely in the protoplasm. 

 For confirmation of this fact, sections are of course required 

 which have only the thickness of one or two meshes. The 

 alleged coloration of the spaces of the meshes, which earlier 

 observers affirmed frequently, is to be attributed to the 

 thickness of their sections, and can be explained without 

 difficulty ; in fact it follows necessarily, if our view of the 

 alveolar structure of protoplasm is to be regarded as correct. 



But how, it will be asked, could Altmann have com- 

 pletely overlooked, on his part, the framework of the 

 protoplasm ? The explanation of this seems fairly obvious. 

 He himself recommends investigating the preparations with 

 " an open cone of illumination," i.e. under conditions which 

 cause all the more minute and pale structural elements, 

 that are stained but little or not at all, to become simply 



