78 MICRO-ORGANISMS AND DISEASE. [CHAP. 



subtilis. The individual elements are about O'Ol mm. long, 

 and 0'002 mm. thick. They are motile just like bacillus 

 subtilis. Although they form chains they do not form proper 

 leptothrix. They occur in putrid fluid. They are very 

 common in the ichor produced by injecting ammonia or other 

 substances producing sloughing and necrosis of the subcu- 

 taneous tissue in the guinea-pig. 



(c) Bacillus septicus occurs in earth, in putrid blood, and in 

 many putrid albuminous fluids. It is non-motile, and is 

 capable of forming leptothrix. The thickness varies from 

 0'004 to O'Ol mm., and its length depends on the number of 

 elements contained in a row. The shortest are about - 004 

 mm. There are various species, differing from one another in 

 the thickness of the elements. They are all anaerobic. The 

 elements, whether in the short rods or in the leptothrix fila- 

 ments, are cubical or rounded. The rods and filaments are 

 markedly rounded on the ends. It forms spores independently 

 of free access of air. The spores are oval, and differ in thick- 

 ness according to the thickness of the bacilli they are formed 

 in. The bacillus is found occasionally in the blood-vessels of 

 man and animals after death. In a nourishing fluid, in which 

 microcdccus, bacterium termo, or bacillus subtilis grows, they 

 have no chance of growing, and even when numerous at first 

 they soon disappear. 



(d) Streptothrix and Cladotlirix. Cohn 1 found in a con- 

 cretion of the human lacrimal canals long, pale, smooth, ap- 

 parently branched threads, either straight or twisted ; they 

 were finer than the threads of leptothrix buccalis ; he called 

 them Streptothrix Foersteri. They are probably identical 

 morphologically with Cladothrix dichotoma. This latter 

 occurs in pond- water containing decomposing organic matter. 

 It consists of long whitish threads fixed on chlorophyll- con- 

 taining algse. The threads when fresh appear smooth, pale, 

 occasionally granular, and on staining they are seen to be 

 composed of shorter -or longer bacilli just like the leptothrix 

 form of bacillus subtilis ; but they are thicker than the 

 bacillus subtilis. Occasionally the ends of the threads are 

 seen not as linear series of bacillar rods, but like bacillus 

 anthracis and the bacillus of blue milk (see below) as chains 

 of torula-like spherical elements. From the threads single 

 motile bacilli are seen to come off. The threads are only 

 apparently branched, since the branches are threads merely 

 stuck on to other threads sideways at an acute angle. A 

 bacillus may be seen to stick to a thread and then to grow 



1 Bcitr. z. Biol. d. Pflnnzen, vol. i. p. 186. 



