696 Journal of Agricultural Research vol. vi, no. 18 



in the autoclave for half an hour at 20 pounds' pressure. Even after 

 this harsh treatment the microscopical picture was practically unchanged. 

 As substrates rich in organic matter, such as beef agar, frequently con- 

 tain symplasm and regenerative bodies resulting from former bacterial 

 growth, they are especially liable to give misleading results. 



DISCUSSION OF RESULTS 



We hope that the facts mentioned in this preliminary communication 

 will suffice to awake an adequate interest among our fellow bacteri- 

 ologists, as there are numerous problems which now can be attacked suc- 

 cessfully from this new standpoint. It is true that several authors 

 before us have already spoken of the "life cycles" of bacteria. In most 

 cases, however, they meant only the straightforward (not "cyclic") 

 development, consisting in stretching and dividing of the cells, some- 

 times combined with the formation and germination of endospores. 

 Fuhrmann (7, 8), who also wrote upon the " Entwicklungskreise" of bac- 

 teria, made some correct observations concerning the formation and further 

 development of the gonidia. He was wrong, however, in concluding 

 that these "granula" which he found in some spore-free bacteria were 

 practically counterparts to the endospores in the "life cycle" of the 

 spore-forming bacilli, and his opinion upon the "detritus" resulting from 

 the disintegrating cells — namely, the symplasm — was far from being 

 correct. In this direction Fokker (5) came much closer to the truth. 

 It is not impossible, of course, that by a thorough sifting of the literature 

 we shall discover some entirely forgotten author who was already on the 

 right track. So far as we know now, only one bacteriologist has previ- 

 ously seen all the different stages of growth typical of the full life cycle 

 of the bacteria. We refer to De Negri's important "Untersttchungen zur 

 Kenntnis der Corynebacterien" (16), which appeared this spring, when 

 we had just begun to prepare this paper for publication. A compara- 

 tive study of the illustrations of his article and those of the present 

 paper will be very instructive. He registered the following forms pro- 

 duced by the organism which causes the "malignous granulom:" 



Large globules (2.5 to 5. 5m) sometimes in sarcina form, 

 eventually developing round or rodlike germs or buds Our types A and B 



Large forms containing granules occasionally unstain- 

 able Our type C 



Crumbly agglomerations formed by large forms "melt- 

 ing" together, which later give birth to new small 

 forms Our type D 



Small globules frequently in chains Our type E 



Small short rods (% by iju), small slender rods (^ by 

 i]4 to 2yu), rods containing granules, curved rods, and 

 rods showing racket form Our type F 



Granulated threads dissolving into small globules Our type G 



Entirely unstained bright rods Our type H 



