BY R. GKEIG SMITH. 667 



like appearance. The broken appearance of the dried and stained 

 rod is veiy characteristic. 



A few of the films that had been made from peptone-glucose 

 fluid cultures showed small terminal prominences that suggested 

 buds, and in order to observe them bettei", the films, instead of 

 being fixed h\ hent, as is customary in preparing bacterial films, 

 were fixed liy means of formalin, the employment of heat being 

 avoided throughout the process. The method consisted in spread- 

 ing a loop oi a •^)6 to IS hours culture upon a clean cover glass 

 and allowino- the film to dry in the air. It was then floated on 

 a 5-10 per cent, aqueous solution of formalin for five minutes, 

 rinsed in distilled water, floated on the stain, again washed in tap 

 followed by distilled water, allowed to dry in the air and finally 

 mounted in balsam. Of the various stains, gentian-violet used as 

 Frankel's carbol-violet gave the best result The blues were 

 rrtther weak, and carbol-fuchsin stained the whole organism, 

 althouo'h.when diluted it did fairlv well. 



The organiitr)it< prepared in this ivay appeared as more or less 

 oval vacuolated yeasts, and a few of the cells showed a ])ronounced 

 terminal bi(d. The yeasts are undoubtedly best seen in the fresh 

 condition, hut the nodule organisms are much too small for 

 observation in this way, and consequently the use of a diflferential 

 stain is necessary. When prepared in this way the single cells 

 vary in length and breadth, but generally are about 0-5 fi broad 

 and from 1-2 to '2-0 fi long. The longer forms consist of several 

 cells contained in a delicate tubular capsule. We can now explain 

 the broken appearances of the organisms when prepared by the 

 methods usually adopted for bacteria. The heat used to fix the 

 organisms causes the protoplasm of the cell to contract, and a 

 break occurs across the vacuole. The sinsi'le oro'anism thus exhibits 

 polar staining. The organisms may have produced a bud more or 

 less mature that separates from the parent cell, but is still retained 

 within the capsule. The stained organism and bud will now 

 appear as a rod, staining centrally and at the poles. The bud 

 may mature and form its vacuole, in which case two organisms 

 will be contained in one capsule. This double organism will stain 



