THE IDENTITY OF BACTERIUM FCETIDUM WITH SOIL COCCI. 151 



once by Thin) were never found in any of the cultures. There can 

 be no doubt that these cocci, similar in size and appearance to the 

 " corpuscules brillants," are identical with them ; their average 

 diameter is 1-35 /x. 



In the next stage a short staff-like rod, 5.0 — 6-0 /x in length and 

 1-0 jji. in width, has appeared in the canoe, and standing out from it 

 at its centre or end and distinguished by its greater brilliancy is the 

 coccus. In early stages of rod-formation the boundaries of the 

 canoe-shaped envelope can still be traced, but they soon disappear. 

 Sometimes more cocci are associated with each rod ; they are then 

 usually placed either singly at its ends or paired at its centre. The 

 cocci can be traced gradually dwindling away, and finally merging 

 with the substance of the rods. 



By simple elongation the Bacterium next reaches its Bacillus 

 stage. The Bacilli are of varying length — on an average about 

 25'0 /A, but this size is often greatly surpassed, some of them 

 measuring as much as 144-0 f*. Already in cultures only three 

 days old their protoplasm is, in some cases, divided into a row of 

 spores reaching from end to end of the cell. These spores — in 

 every way resembling the " corpuscules brillants " — are discharged 

 in great numbers by the collapse of their investing sheaths. 



The other method of the rods' growth described by Dr. Thin, 

 viz., their fragmentation to form small clusters, was also observed by 

 me, but not frequently. 



A series of figures illustrative of the chief forms assumed by the 

 soil-ferment in its development were di'awn with the camera for 

 comparison with the figures on Dr. Thin's plate. The resemblance 

 in every way between the two series was most striking This plate 

 having unfortunately been lost, it would not be possible to replace 

 it without repeating the cultures, for which I have no present 

 opportunity. 



It is necessary to say here that I in no way assert soil-cocci to be 

 referable to Bacterium fcctidum, for I quite agree with the remark of 

 a great physiologist, that my results would equally prove the non- 

 specificity of Dr. Thin's organism as the specificity of the cocci. 



The cocci obtained by scraping fetid socks developed the same 

 series of forms as did the soil-ferment, thus proving that I really had 

 Dr. Thin's organism to work with — a very important matter, as the 

 immediate sequel will show. 



Chemical proof of the identity of Bacterium fcptidum Thin with the 

 cocci of the soil. 



This part of the method consisted in testing the chemical 

 deportment of soil-ferment, and of the Bacterium, when cultivated 

 in various fluids, in the warm chamber at approximately the same 

 range of temperature as above mentioned. The identity is shown 

 in three ways — 



(i) Both are capable of reduciiuj nitrates to nitrites. — Into a test- 

 glass containing soil-ferment growing in sterilised vitreous humour 

 was introduced, under suitable precautions, a small quantity of a 

 20 per cent, solution of potassium nitrate. After six days' interval 



