1878.] 



Bacterium termo and Micrococcus. 



475 



led me to conclude not only that B. termo had a life-history similar to 

 that of Bacillus anthracis, but also that Billroth was probably right in 

 believing that Micrococci were the spores of ordinary Bacteria. 



I have already proved * that Bacillus anthracis, like B. subtilis, and 

 the Bacillus found by Dr. Klein on animals suffering from pneumo- 

 enteritis (pig typhoid), is, though rarely, an active organism, the motile 

 phase appearing at irregular intervals ; that the protoplasm of the long 

 filaments into which, the rods lengthen divides into segments, which, 

 either at once or after again dividing, condense into spores ; that the 

 spores before germinating may divide into sporules, and that the new 

 rod is not formed, as stated by Dr. Koch,f out of the gejatinous- 

 looking envelope, but out of the spore itself — the spore germinating, 

 and pushing out a process from one of its ends, which carries along 

 with it the thin capsule, converting it into the sheath of the rod. 



Before attempting to compare the life-history of Bacterium termo 

 with what we know of the life-history of Bacillus anthracis, it was 

 necessary to have B. termo isolated from all other organisms. After 

 •many failures, I was fortunate enough to find a cultivation in which 

 the rods of B. termo were alone visible. After keeping this cultivation 

 under observation for some time, others were made by infecting fresh 

 drops of humor aqueus, previously placed on absolutely clean covering- 

 glasses, with as small a drop of the liquid as possible on the point of a 

 needle. The covering-glasses were inverted over "cells" made by 

 fixing glass rings to ordinary slides by means of Brunswick black, the 

 cells having been carefully washed immediately before use with abso- 

 lute alcohol. A thin layer of olive oil between the edge of the glass 

 ring and the covering- glass prevented evaporation and the entrance 

 of moisture and solid particles from the surrounding atmosphere. 



In cultivations of B. termo prepared in this way, and kept at a tem- 

 perature of 30° C, I made out that, under certain conditions, the rods, 

 instead of undergoing fissiparous division, lengthened into filaments, in 

 which in due time spores appeared. (Plate 10. Series V, h, i.) The fila- 

 ments were shorter than those of B. anthracis, and they never showed any 

 tendency to form a network or mycelium. The spores were extremely 

 small, bright, almost spherical bodies. In from two to three days after 

 their formation the spores escaped from the filaments, and either lay 

 isolated near the centre or formed a zooglcea (Series VI, h) at the edge of 

 the cultivation. Having been free for some time, they germinated into 

 short slender rods. (Series V, b, c.) The young rods did not at once 

 lengthen into another generation of spore-bearing filaments, but, be- 

 coming active, they multiplied by transverse fission. (Series V, d, e.) 

 The filaments packed full of spores often resembled " Micrococcus 

 chains," and only differed from filaments containing spores, which I 



* " Quart. Journ. Micro. Science," April, 1878. 



f " Beitrage zur Biologie der Pflanzen," II, 2, 1876. 



2 I 2 



