666 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 27 



Potato broth. — Growth slow, with sHght uniform clouding and slight 

 sediment. 



Potato. — Feeble, grayish growth. 



Gelatine stab. — No liquefaction. 



In asporogenic cultures of B. alvei coccoid bodies were observed which 

 morphologically resembled the coccoid bodies observed by Lochhead ((5), 

 but attempts to isolate this form have thus far been unsuccessful. 



In recently formed asporogenic cultures the protoplasm (from bouillon 

 or glucose agar) was usually homogeneous. After several transfers, 

 especially on egg-yolk agar, the protoplasm often became granular or 

 broken. At times the rods assumed a beaded appearance resembling 

 chains of coccoid cells. One culture in brood-filtrate medium assumed 

 a decided coccoid appearance with many forms indistinguishable mor- 

 phologically from chains of coccoids observed in cultures of 5". apis. Rods 

 were frequently observed in a state of dissociation, and in some cultures 

 few rods remained undissociated after 4 or 5 days' incubation. 



Pleomorphism in Streptococcus apis. — On ordinary bouillon agar 

 .y. apis, when freshly isolated, appears in diplococcoid form with occa- 

 sional single cells and short chains. The cells are only rarely spherical, 

 their length being usually aproximately lj4 times their thickness. In 

 bouillon broth the tendency to grow in chains is accentuated, while on 

 nutrient agar containing egg yolk the cells are smaller than in bouillon 

 agar and appear singly or in pairs. The ends are sharply rounded and 

 frequently pointed, many forms being morphologically indistinguishable 

 from B. pluton. In some of the cultures on egg-yolk agar approximate- 

 ly 50 per cent of the cells became more or less pointed after multiplication 

 ceased. (Plate 6, E.) After prolonged cultivation further changes in 

 morphology have been observed from time to time. 



Wharton {14) reported that his morphological studies suggest the 

 identity of B. pluton and B. alvei and stated that "Cultures of B. pluton 

 have been observed to change to B. alvei form, resembling biologically 

 the B. alvei isolated from infected larvae." In a few instances the 

 writer's cultures of 6". apis derived originally from isolated colonies have 

 yielded rods (Plate 6, K) and eventually spores of B. alvei. This has 

 been observed only in broth cultures prepared by transfer from old 

 cultures on nutrient agar. After incubation for 7 to 12 days at 27° C, 

 rods of B. alvei appeared in small numbers, but nothing was determined 

 concerning their origin. Spores were produced in the original broth 

 cultures and in transfers on nutrient agar. On other occasions rods that 

 failed either to grow or to produce spores in transfers originated in 

 broth cultures. Occasionally rods with length equal to about five times 



