724 REPORT— 1893. 



Grsrame. 



Formic acid 0-0306 



Acetic acid 0-2402 



Butj-ricacid 0-0134 



Lactic acid 0-7907 



Total . . . 1-0749 



We find in actual worli that tlie quantity of acid produced varies from one to 

 three grms. per litre. 



We found that an unorganised ferment, ' cerealin,' changes the starch of the 

 hran into glucoses and dextrin ; the bacteria then ferment the glucoses, splitting 

 them up into the gases and acids alread}' mentioned. 



B.furfuris has no action on the cellulose of the bran, nor on the skins, as some 

 bacteria in the bate have ; in every case where the skin is attacked it is putrefac- 

 tive or gelatine liquefying bacteria introduced from the bate, or in specially 

 favourable circumstances (hot, sultry -weather) developing from germs always pre- 

 sent in the atmosphere. The gases evolved have only a mechanical action on the 

 skin, floating and distending them, and so enabling them better to take up the 

 acids. In carrying out this -work we discovered a delicate test for lactic acid. 



The presence of lactic acid was shown in the following manner : — 10 c.c. of the 

 liquid were placed in a small distilling flask along with 2 c.c. strong II^SO; and 

 about 0-5 grm. potassium chromate in a little water. This was distilled and 

 the vapours received in a test tube surrounded by cold water; on adding magenta 

 solution discolourised by SO., to the liquid in the test tube a red colour was pro- 

 duced by the aldehyde formed from the lactic acid ; aldehyde was also recognised 

 by its smell. We tind this an exceedingly delicate test for lactic acid, and as far 

 as we know it is quite new in this form. 



For 10 c.c. of liquid to be examined we find 2 c.c. strong HoSO^ and 1 grm. 

 of potassium chromate to be the best proportions. Formic, acetic, propionic, 

 butyric, valerianic, succinic, malic, tartaric, and citric acids do not give the 

 reaction. 



In conclusion, there are no doubt other organisms capable of fermenting a bran 

 infusion in a somewhat similar way, and the work of isolating and separately 

 examining their life-history and products yet remains to be done. 



9. On some Ferments derived from Diseased Pears. 

 By Geoege Tate, P'h.V., F.C.S. 



From diseased pears the author has isolated, among other micro-organisms, 

 three which possess morphological and chemical interest. 



(1) A yeast {Saccharomyces viscosus) which is characterised by forming small 

 cells of an average length of 0-003 mm. and white, strongly viscid growths 

 upon solid nutrient media. It brings about no alcoholic i'ermentation of the better- 

 known sugars, but inverts cane sugar. It can propagate either by budding or by 

 endogenous division. 



(2) A bacterial organism (Ascococcus luf.eits) forming yellow growths upon 

 nutrient gelatine. Growths of two types have been obtained, one showing 

 nscococci, the other only rods. It is an acid ferment of dextrose and mannitol. 



(3) A bacterial organism forming white growths upon nutrient gelatine. Two 

 types of growth have been obtained upon nutrient media, one in which micrococci 

 and rods predominate, another in which the tendency to form ascococci is strongly 

 marked. These two types are represented by widely diff'ering macroscopic cultures 

 upon solid media. Botli forms behave as lievo-lactic ferments towards dextrose 

 and mannitol. 



The organism is an inactive-lactic ferment of rhamnose, but after such action 

 still retains its power of decomposing dextrose into Irevo-lactic acid. 



