882 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Zygospores were also found, under cultivation, on Sporidinia 

 grandis (growing on Lejnota procer(i), Sjnnellus fusiger (on ColUbia 

 fusipes), and large quantities of zygospores on Synceplialis, parasitic 

 on Bhizopus nigricans. 



New Schizomycete, Leptothrix gigantea.* — W. Miller describes 

 under this name a new schizomycete found in the teeth of a dog 

 suffering from the disease known as Pyorrhoea alveolaris. He sub- 

 sequently found it in the bite of other herbivorous and carnivorous 

 animals, and was able to cultivate it. It approaches very near to 

 Beggiatoa alba and Crenothrix Kiihniana, and was in certain cases 

 foimd distinctly invested in a sheath. The chief interest of the 

 observations was that they confirmed Zopf's f view that all the various 

 forms of bacteria are but stages of development of the same organism. 

 All stages of intermediate forms between the leptothrix, bacterium, 

 and coccus form were observed ; and even transformation into the 

 spirillum, vibrio, and spirochfete forms. 



Bacterium Zopfii.+ — In the vermiform appendage of two hens 

 which had died from an epidemic disease, H. Kurth found a bacterium 

 which he describes as a new species, under the name B. Zopfii. He 

 was able to trace in it clearly not only the genetic connection of 

 the bacilli and cocci, but also the conditions in which the one or the 

 other form arises ; the bacillus form being the reproductive, the 

 coccus the resting form. "When bred in a nutrient gelatine of one 

 per cent, extract of flesh at 20° C, the bacilli develope from the 

 point of infection in radial threads with remarkable power of cohesion, 

 finally forming a ball of dense coils. In a fluid nutrient substance 

 the bacilli disconnect themselves and acquire a swarming motion. 

 At a temi)erature of 35° C. this movement gradually ceases, and short 

 threads are formed which sway about in the fluid. When the nutrient 

 fluid is exhausted, the threads break up into bacilli, and each divides 

 again into two cocci, which remain united ; and the same takes place 

 also in gelatine. In a fresh nutrient substance bacilli are again pro- 

 duced from the cocci. This species of bacterium appears to have no 

 pathogenous effect. 



A strong confirmation of Zopf's views § with regard to the genetic 

 connection of the various forms of Schizomycetes is furnished by the 

 fact that we have here, as modifications of the same original form, 

 sim^ile globular cells, motile rods, quiescent and motile longer threads, 

 and rigid spiral forms, as stages of development in a single species, 

 resulting from variations in the nature and composition of the nutrient 

 fluid ; i.e. from differences in its quantitative rather than in its quali- 

 tative composition. 



The distinctness of B. Zopfii from other forms of bacterium can 

 be best seen by culture in a 2 per cent, gelatine extract of flesh, in 



* Ber. Deutsch. Bot. Gesdlsch., i. (1883) pp. 221-6 (1 pL). 

 t See this Journal, ante, p. 688. 



X Ber. Deutsch. Bot. Gesellsch., i. (1883) pp. 97-100 (1 pi.) ; and Bot. Ztg., 

 xli. (1883) pp. 369-86, 393-405, 409-20, 425-35 (1 pi.). 

 § See this Journal, ante, p. 688. 



