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Dr. G. S. West and Mr. B. M. Griffiths. [July 7, 



homogeneous structure (tigs. 13 and 14). There appear to be several firm 

 layers, with intervening layers which become somewhat gelatinous on the 

 addition of carbolic acid. The innermost layer is a firm one, but the outer- 

 most layer, which can only be demonstrated by special methods, is apparently 

 gelatinous.* 



Nothing of the nature of a definite nucleus is present in the cell, but as the 

 protoplasmic network includes many conspicuous granules, very careful tests 

 for nucleins have been made. 



Staining has given very indefinite results. Erythrosin and methylene 

 blue were of little use. Safranin and carbol-fuchsin were found the most 

 useful stains, and double staining with safranin and gentian-violet gave good 

 results. Carbol-fuchsin stains the protoplasmic network very well, but in no 

 instances were the included granules distinctly brought out. Cover-glass 

 preparations gave much better results than any other method. The granules 

 of the network do not appear to have an affinity for any of the stains used, 

 and they cannot be regarded as chromatin granules. 



Microchemical tests for nucleo-proteids have been carefully repeated many 

 times, using cultures of the organism fixed in 2^-per-cent. commercial 

 formalin. As stated before, by this means the sulphur globules are removed 

 and the fixed protoplasmic network can be experimented upon. Owing 

 to the impermeability of the cell-wall it was found necessary to allow the 

 operations to extend over a considerable period. 



Treatment with concentrated sodium carbonate removed fully nine- 

 tenths of the granules, while the network remained clear and refractive 

 (fig. 21). 



A 10-per-cent. salt solution removed a large proportion of the granules, 

 probably about five-sixths of them, and the network was again left clear 

 except in the central part of the cell, where there appeared to be a concen- 

 tration or shrinking together of the protoplasmic strands (figs. 10 and 11). 

 For this reaction, and also the previous one, the cultures were exposed to the 

 reagent for rather more than 14 days. 



Treatment with dilute potash (5 per cent.) gave a variety of results due 

 probably to the degree of penetration of the potash in different individuals. 

 In most cases, after about 10 days, the granules were for the most part 

 dissolved, and the network to a great extent disorganised (fig. 12). 



A number of cultures were treated with acidulated pepsin-glycerin, and 

 in these cases the network was for the most part digested, whereas the 

 majority of the granules remained unchanged. Where the network had only 



* There is evidence of this even in the active state of the organism, as the cells have 

 a tendency to stick to the bottom of the vessel in which the culture is growing. 



