CONTRIBUTIONS TO THE CYTOLOGY OF THE LAOTEEIA. 447 



One of the first orgailisms to wliicli I tlieu turned my 

 attention was the large Spirillum which inhabits the hind 

 gut of the common cockroach^ Stylopyga orientalis. I 

 hoped — from the large size of this organism, and from the 

 descriptions which have been given of it by others^ — that I 

 should find some new and illuminating structures in this 

 Spirillum. But my hopes have not been altogether 

 fulfilled. 



The only structures which I have been able to make out in 

 this form with absolute precision are essentially the same as 

 in the form from frogs and toads. The Spirillum of the 

 cockroach possesses an exceedingly thick cell wall, which has 

 a strong affinity for many stains, and which renders it very 

 difficult to study cytologically. I have obtained the most 

 satisfactory results with wet films fixed in sublimate-alcohol 

 and stained with iron-hasmatoxylin. But differentiation of 

 the contents of the cell is very difficult to obtain, and succeeds 

 only occasionally. It has usually been my experience that 



' According to Guilliennond (1907) and otliers. an organism contain- 

 ing a typical nucleus has been descril^ed by Kiinstler and Gineste 

 ('C. R. Assoc. Anatomistes,' 1904'), under the name Spirillum peri- 

 planeticnm. from the intestine of Periplaneta orientalis. 

 Unfortunately I have not been able to see this paper. In two sub- 

 sequent notes, however (Knnstler and Gineste, 1906. 1906a) these 

 aiitliors describe and figure this organism, but do not mention or dei)ict 

 a nucletis, and give the host as P. americana. In the first note 

 (1906) a reticular structure of the cytoplasm is figured and described. 

 In the second note (1906a) " spherular elements " are described in the 

 cytoplasm, and the avei'age dimensions are given as 8 /x x 3 /i. It is 

 possible that this is the same organism which I call the "large Spiril- 

 lum from St. orientalis," biit I cannot be certain from the in- 

 complete notes of Kunstler and Gineste which are at my disposal. 

 Fantham (' Quart. Journ. Micros. Sci.,' 1908) casually describes " spiril- 

 lar forms occurring in the hind gut of the cockroach." He obsei-ved 

 "a diffuse nucleus . . . consisting of a number of chromatin 

 masses seen to be connected Ijy a lightly staining spiral in successfully 

 stained specimens. At other times the achromatic thread was not 

 evident." Diagrammatic figures are given. They are not like anything 

 I have seen in Spirilla from S. orientalis. I do not attach any 

 importance to these fragmentary observations. 



