CONTRIBUTIONS TO THE CYTOLOGY OF THE BACTERIA. 475 



granules connected by deeply stained cytoplasm — as main- 

 tained by Guilliermond (1908). As I liave not myself made a 

 study of the forms which Swelleng-rebel describes, and as his 

 work has evidently been conducted with considerable care 

 and thoroughness, I hesitate to make any more definite 

 ■criticism of it at present. 



The earlier observations of Biitschli (1890, 1896), Wahrlich 

 (1890), Zettnow (1897), and others are in agreement with 

 mine^ if it be assumed — as appears highly probable — that 

 they investigated only those forms of Bacteria which possess 

 a chromidial nucleus. With Biitschli's interpretations, how- 

 ever, I cannot agree. 



Nuclei in the form of a few small granules in each cell, 

 described by Meyer (1897, 1899), and Preisz (1904), are 

 probably of the same nature as chi'omidial nuclei, and 

 the nuclei which occur in the Bacilli of modified flexilis 

 type. 



The facts and their interpretations, given by Nakanishi 

 (1901) are — in many cases — closely parallel to my own. 

 Nakanishi found filamentar nuclei in Bacilli (e.g. B. 

 anthracis), and in Spirilla spherical and filamentar nuclei, 

 which are very like the structures which I have myself ob- 

 served in similar forms. After ably discussing his observa- 

 tions, Nakanishi arrived at an interpretation which agrees 

 with mine. 



How far the observations of Amato (1908) can be brought 

 into line with my own I do not know. It is possible that 

 the '^ nuclear" structures which he describes are really meta- 

 chromatic granules — as suggested by Guilliermond (1910). 



A point of considerable importance is to be found in the 

 work of Schewiakofl: (1893). In Achromatium, he found 

 a number of minute chromatin granules scattered through the 

 cytoplasm — in other words, he found a nucleus of the 

 chromidial type. He observed that these granules undergo 

 division — which is a further important piece of evidence 



^ So far as the actual morpliology of some of the smaller Bacteria 

 is concerned. 



VOL. 56, PART 3. — NEW SEEIES. 33 



