318 



to be observed. The stiidy of this bactery is still imperfect and I mention it cmly be- 

 cause it might be taken for B. septicus. 



For the object I have in view, I studied in particular B. septicus. while I think^ 

 that there is not one indication in bacteriological literature which suggests any 

 benificient effect of free oxygen on the functions of this bacillus. For the skatol- 

 bacteria on the other hand, such indications exist. It seems at least according 

 te some authors, that certain varieties of the nearly allied and commonly obliga- 

 tous anaërobic tetanus-bacillus, are suscept to change into aerobics, a transformation 

 which I witnessed myself by other varieties isolated from putrefying albumen. More- 

 over B. septicus is a »bona species«, i. e. recognisable for everybody. 



B. septicus is exceedingly mobile and generally consists of staves, covered all 

 over with ciliae. Spores grow easily, especially when there is contact with air. They 

 are more oblong than globular, mostly enclosed in the somewhat swollen ends of the 

 staves, and surrounded by a hoUow space. Though this bacillus is evidently polari- 

 cally constructed, it moves spore-end or tail-end forward, and may suddenly change 

 the direction of the movement. When a little air accedes, the staves may grow out 

 into long threads and the motion ceases. 



With a total withdrawal of oxygen there is a dispositon for the formation of 

 clostridia,.but without a marked difference between an »oxygenform« and a »clostri- 

 diumform» as found in Granulohacter butylicutn. 



If the nutriënt matter is merely albumen or pepton, gases are produced, who?e 

 quantity increases more or less by the addition of glucose. 



Fibrine and proteids produce volatile sulphides, sometimes in great profusion r 

 production of merkaptan, too, is observed under unknown circumstances. The colonies 

 liquefy the gelatine of the above composition ; their surface is quite characteristically 

 pointed, evidently because many small shoots pierce slightly into the gelatine, before 

 the melting sets in. This may be compared with the behaviour of anthrax, where, 

 however, there is no melting at all. Commonly whether spores or vegetative cells are 

 sown out, only few germs develop, which proves, that the nutriënt matter itself, — 

 even the best I could procure, — acts in an high degree as a »bactericid« in relation 

 to B. septicus. The growth is slow, even at brooding ternperature, when compared ta 

 allied aerobics. 



Concerning the necessity of oxygen for B. septicus and the skatolbactery, I could 

 state what follows. 



B. septicus T observed as well with regard to the figures of respiration, as to the 

 growth. Tn both ways the microaërophily could with certainty be stated. As this 

 bacillns is extremely mobile, and as the spores render the swarms of bacteria very 

 opaquc, the study of the figures of respiration ofïers no difïiculty. 



A smail nunibcr of bacteria accummulating in the centre of the preparation, pro- 

 duce the impression of aërophoby. If on the contrary, the bacteria are very numerous, 

 a circular accumulation is formed at some distance from the edge of the cover-glass 

 and the mcniskus, pointing out the place where the tension of oxygen is optimum. 

 ]f we examinc the inner field, i. e. the part surrounded by the accumidation and 

 totally deprivcd of oxygen, there, too, all is in motion. This motion is however much 

 slower, more staggering and uncertain, than in the accumulation itself. I think that 

 this inner part is continually >upplie(l with individuals from the accumulation, which 



