162 Dr. Schunck on the Action of 



stance be mixed with water, and the mixture be allowed to stand 

 for a length of time in a warm place, signs of a more active 

 process of fermentation begin to show themselves, especially in 

 summer weather; bubbles of gas are given off, and a peculiar 

 smell is emitted, which, though disagreeable, cannot exactly be 

 called putrid. During this process, which is evidently one of 

 putrefaction in the stricter sense, the erythrozym loses its slimi- 

 ness, and is converted into a red flocculent mass, which may 

 easily be separated by filtration from the liquid. The latter is 

 clear, colourless, and quite neutral. After erythrozym has passed 

 through this second stage of decomposition, its power of decom- 

 posing rubian is found to have lost much of its intensity. It is 

 during the first period of its decomposition, when no apparent 

 change is taking place, that this power is most energetically 

 exerted. During the second, or more strictly putrefactive stage, 

 it acquires, however, the property of decomposing sugar. If 

 erythrozym be mixed with a solution of cane-sugar, and the 

 mixture be allowed to stand for a considerable time until gas 

 begins to be disengaged, the solution acquires by degrees a 

 decided acid reaction.'' The great interest attaching to bodies 

 of this class induced me to examine this action of the ferment 

 on sugar more minutely, and I have now the honour of laying 

 the results of my investigation before the Society. 



In order to obtain the ferment for the purpose of decomposing 

 sugar, it is not necessary to prepare it by precipitation with 

 alcohol, as I recommended in my paper on rubian, nor to pay 

 much attention to its complete purification. I found that the 

 following method of preparation yielded a product perfectly well 

 adapted for the purpose. A quantity of madder (French being 

 the kind employed) having been placed on a calico strainer, 

 water heated to about 100° F. is poured on it in the proportion 

 of about four quarts of water to every pound of madder. To 

 the dark reddish-brown liquid there is now added a small quan- 

 tity of muriatic acid. This produces a brown flocculent preci- 

 pitate, which is allowed to settle, and after the liquid has been 

 decanted, it is washed with a quantity of fresh water, the pro- 

 cess being repeated until the excess of acid has been removed, 

 after which the precipitate is collected on a calico strainer. After 

 the water has run off, there is left on the strainer a thick brown 

 pulp. This pulp contains, besides erythrozym, small quantities 

 of pectic acid, colouring matter, &c., but these impurities are of 

 no material consequence as regards the process of fermentation. 

 It differs from the ei-ythrozym prepared by precipitation with 

 alcohol in containing no lime or other base, the latter having 

 been removed by the acid used for precipitation. In my expe- 

 riments, however, I always added a certain proportion of lime- 



