220 



THE PATHOGENIC FLAGELLATES 



tures make them relatively easy to study, and the conclusions that 

 have been drawn are comparatively free from imaginative diversions, 

 and for this reason they are the best representatives of the group for 

 descriptive purposes. 



Fig. 87 



Spirocheta anodontce. X 1500. (After Fantham.) The membrane winds around the body 

 in right-handed spiral; chromatin rodlets and basal granules shown. 



A. Structures of Spirocheta Balbianii, Certes, 1882.— This 

 organism, first studied by Certes as a trypanosome, may be found in 

 the anterior part of the oyster's digestive tract, where, if present at all, 

 it is usually in the crystalline style. Both Perrin ('06) and Fantham 

 ('08) note that the organisms soon disappear after the oysters are 

 removed from sea water. 



The spirochete is a spirally wound thread from 50 to 150 jx long 

 and about 2 to 3 ^ wide. The inner protoplasm contains a number 

 of transverse bands of chromatin, about 60 in all, which Perrin, 

 erroneously, calls "chromosomes," and which constitute the sole 

 nuclear apparatus of the organism. Sometimes these bands run 

 together to form a more or less complete helix of chromatin; again, 

 they are completely divided in preparation for longitudinal division 

 of the cell; but at no time do they come together to form a definite 



