go DISSOCIATIVE ASPECTS OF BACTERIAL BEHAVIOR 



If the gonidia are maintained under conditions involving lack of nutriment, as, for in- 

 stance, in aged cultures (thus preventing their entrance into a higher cyclostage), or if they 

 are submitted to the influence of prolonged warming at 37° C, they become transformed into 

 new and smaller elements, the gonites. The number of these forms increases with the gradual 

 decrease of the gonidia. In cholera cultures left standing in the laboratory for a month or 

 more, one finds that a great number of gonites have been produced. They are all extremely 

 small, carry a much reduced amount of cytoplasm, and the smallest are known as the 

 "microgonites." If the original culture is placed in sunlight, the same result occurs in a 

 much shorter time — sometimes within a few days. The gonite is unable further to repro- 

 duce itself as such. When cultures that have entered completely the gonite stage are trans- 

 planted to agar, no growth occurs. Such cultures appear to be destitute of living cells. If, 

 however, such a gonite culture is transplanted to broth, the gonites undergo further de- 

 velopment, within a period of five to seven hours, into two new forms — namely, the spermite 

 ($) and the oite (+). In a liquid medium copulation occurs, and the fertilized cell is capable 

 of soon regenerating the original cell type. Here, then, we have a strict sexual form of re- 

 production. Enderlein has followed the details especially in the cholera vibrio. 



With further reference to the foregoing considerations, it may be said that the re- 

 productive significance of the gonidia in bacterial reproduction is now beyond a matter 

 of doubt. These bodies have been observed repeatedly, and their subsequent develop- 

 ment into the original cell type followed by several competent investigators. As for 

 their further transformation into the gonites, and the subsequent transformation of 

 these into the sex cells — although this phenomenon eventually may be found to occur, 

 and to underlie a true sexual form of reproduction in the bacteria — in so important a 

 matter one is justified in postponing a conclusion until the striking observations of 

 Enderlein can be confirmed in the cholera vibrio and extended to other species. It may 

 be remarked here, however, that many of Enderlein's cytological observations have al- 

 ready been confirmed by Schumacher/ And in this case the confirmation is the more 

 valuable since Schumacher was not acquainted with the work of Enderlein at the time 

 of his own studies. 



The cytological aspects of microbic heredity have also been furthered in recent years by 

 the valuable researches of Mellon in a series of contributions extending over many years. 

 Among other matters of importance, Mellon's investigations have dealt especially with a 

 mode of reproduction involving conjugation and zygospore formation, following many of the 

 details of isogamic conjugation in higher forms. These zygospore-like bodies are probably 

 identical with similar forms pictured less clearly by many earlier workers; perhaps with the 

 Pettenkofer bodies described more recently by Kuhn.^ Mellon conceives that the origin of 

 the zygospore is through the fusion of adjacent cells of a filament, sometimes indirectly by 

 means of a peduncle. The bodies seem to be formed equally among the small and the large 

 rodlike elements in the culture. They are often small, but in certain diphtheroids, as ob- 

 served by Massini and by Mellon,^ and in B. diphthcriae (Park No. 8), as observed by my- 

 self,-* they may attain a diameter of 6-7 /i. By favorable staining they usually reveal a 



' Schumacher, Josef.: Centralbl.f. Bakleriol., Abt. I, Orig., 97, 81. 1926. 



^Kuhn, Philaethes: Centralbl.f. Bakleriol., Abt. I, Orig., 93, 280.* 1924. See also: Arch. f. 

 Schijfs- u. Tropen Hyg., 30, 133. 1926. 



3 Massini, R.: Arch.f. Hyg., 61, 250. 1907; Mellon, R. R.: /. Bad., 2, 81. 1917. 



4 Hadley, Philip: loc. cit. 



