152 THE IDENTITY OF BACTEEIUM FCETIDUM WITH SOIL COCCI. 



the liquid was tested for nitrite, into which it was fouud that part 

 of the nitrate had been converted. Bticlcriuin /(vtiihm, simiLirly 

 treated, yielded the same result, but the amount of nitrite liberated 

 seems to be less than in the former case, a few minutes elapsuig 

 before the starch iodide was fully formed.- 



(ii) Both reduce sulphates tu sulphites, and phosphates to phosphites. 

 — Small quantities of a 20 per cent, solution of magnesium 

 sulphate were introduced into two test-glasses containhig sterilised 

 vitreous humour, charged in one case with soil-ferment, in the other 

 with the Bacteriwn. It was ascertained that part of the sulphate in 

 either was reduced to sulphite after the lapse of three days. 



Some Pasteur's fluid was prepared without sugar ; after growing 

 in it both soil-ferment and the Bacterium, for a few days, part of the 

 sulpliate (magnesium) in either was found reduced to sulphite, and of 

 the I phosphates (calcium and potassium) to phosphites. 



Into some filtered perspiration were placed soil and four drops 

 of a 10 per cent, solution of magnesium sulphate. Part of the 

 sulphate was soon converted mto sulphite. Sulphated perspiration 

 charged with the Bacterium likewise gave the test for sulphite. 



(iii) Both liberate lanje quantities of ammonia from the Jluids in 

 ichich theij (/row. — This was proved by many experiments with 

 sterilised vitreous humour, and also with perspiration. In all cases 

 a copious precipitate was obtained with Nessler's test, after a few 

 days' groAvth of soil-ferment and the Bacterium in the fluids. Com- 

 parison of these charged fluids with uncharged test-fluids similarly 

 treated, showed that all or by far the greater part of the ammonia 

 was disengaged by the growth of the soil-ferment and Bacterium, 

 and that none resulted from manipulation. 



In all cultures of perspiration the initial acidity gave place to 

 alkalinity, due doubtless to formation of ammonia in them. 



General Considerations. 



According to the doctrine here advanced, access of the ferment 

 to the sole of the foot must take place by the penetration of fine 

 dust containing ferment through the seams of boots. That this 

 does occur is beyond a doubt ; for not only is the ferment of 

 universal occurrence in surface soil derived from de230sits belonging 

 to all the great geological horizons, but cocci are always to be found 

 upon the feet, even under the most cleanly conditions. 



Whether the ferment has any relation of causation to an 

 abnormal escape of fluid from the soles is a very obscure problem. 

 In the case of people who perspire copiously, the ferment, silting 

 through the boots and not assiduously removed, would find itself 

 bathed by a fluid in which it could freely grow. "We have seen 

 that one result of its growth is the liberation of ammonia in con- 

 siderable quantities. But the alkaline reaction of the fluid, being 

 doubtless due to the presence of this ammonia, is no evidence to 



* Starch and potassium iodide exposed in the room in which the experiment 

 was perfoimed showed not the least trace of blueing until after the lapse of 

 some time. 



