ALTMANN'S GRANULES 223 



Altmann's granules of some cells have been crushed 

 into the nucleus, in which case they look as if they 

 formed part of it, or were inside it a fallacy which has 

 given rise to great controversy regarding the nature of 

 these granules, to the statement that they do not exist 

 in some cells, e.g. lymphocytes and cancer cells, and to 

 failure of appreciation of the fact that the chromosomes 

 are formed out of them. Let mitosis be induced in 

 a living cell and no second glance will be required 

 to realise the real sequence of events. 



The mitosis of plant-cells seems to go on within 

 the nuclear wall, but this is not the case in the animal 

 cells which we have seen. The granules in the cyto- 

 plasm of Altmann 's granules are larger in some classes 

 of cells than in others. For instance, they are much 

 larger in eosinophile leucocytes than in lymphocytes. 

 When they are large their position is obvious, but when 

 they are small, as in lymphocytes and cancer-cells, 

 during the killing of the cell as it is fixed the small 

 granules which are composed of chromatin adhere 

 to and are merged into the nucleus. No matter how 

 we try to fix a specimen, death takes time, and the 

 liquefying cytoplasm bulges out the cell-wall. The 

 rapidity of death depends upon the diffusion of the 

 fixative into the cell, and this diffusion takes time. 

 Hence when a cell is stained and fixed, it appears as 

 if its nucleus is a mass of chromatin which it 

 is not and its halo of cytoplasm, which has bulged 

 out of the cell- wall, is now apparently devoid of 

 Altmann's granules. This is a pitfall into which we fell 

 ourselves, for, although we had seen the granules of 



