36S M. Latour's ObservcUlons on the Cause and 



had a constant tendency to rise to the surface of the wort so long 

 as the fermentation continued, and he is inclined to believe that 

 this tendency is owing to the disengagement of the gas of the 

 globules which are suspended in the wort. He also thinks that 

 he has perceived that these globules, whilst agitated in the wort, 

 diminish in size by contracting, and that, as the result of this 

 contraction, they emit, in the liquid space, small seeds (semi- 

 nules) or reproductive bodies, which, after having vegetated 

 and attained the diameter of the original globule, had the faculty 

 of developing themselves in the way of successive buds, and of 

 so producing, as we have already said, minute moniliform vege- 

 tables. As we have seen, the author admits these two distinct 

 methods in the reproduction and multiplication of the minute 

 vegetable in beer-ferment, — both that by small seeds, and that 

 by germination or budding ; an observation which appears the 

 more interesting, as it is in perfect keeping with the twofold 

 mode of reproduction of all the simple microscopic vegetables 

 situated at the limit of the scale of vegetation. 



If M. Cagniard Latour had not thought himself obliged to 

 answer the questions proposed about the vegetable or animal 

 nature of the globules of the yeast, we should have ventured 

 to have blamed him for spending too much time in discussions 

 which appear idle ; for the discussion is concerning organized 

 productions, which, being neither common esculents, nor mam- 

 miferous animals, can be distinguished only by what they them- 

 selves really are, isolated in nature, and without regarding our 

 conventional characters of vegetables and animals. It would 

 have been more suitable to have said, Y east is not a simple sub- 

 stance or chemical product, as has been thought. What ap- 

 pears a dry and soft paste is an agglomeration of vesicular 

 globules, without locomotive power, organized, because suscep- 

 tible of absorption, assimilation, and increase by the addition of 

 joints, and finally, of reproducing and multiplying themselves ; 

 in short, according to the prevailing opinions, — a vegetable. 



After having demonstrated that ferment or yeast is an accu- 

 mulation of minute vegetables, or at least of bodies capable of 

 producing them, the author proceeds to some observations which 

 are purely chemical. He remarks, \st. That yeast acting upon 

 sugar loses its nitrogen, as is generally known ; 2 J, That all ve- 



