166 DEPARTMENT OF AGRICULTURE. 



REMARKS. 



In a general way it may be stated that all abnormal appearances observed in the 

 fluids examined were such as might be attributed to putrefaction. Although much re 

 mains to be learned as to the causes and nature of this process, the tendency of modern 

 science is to class it as a species of fermentation, which may be denned as a particular mode 

 of decomposition of organized bodies, accompanied by the growth of cells of a fungoid char 

 acter, supposed to be the active agents in the process. 



In fluids undergoing the alcoholic, the acetic, lactic, or butyric acid fermentations, in 

 wine affected with the bitter fermentation, or in a solution of tannic acid changing to 

 gallic acid, we find minute cells, in German called &quot; Hefe,&quot; in French &quot;mycoderms,&quot; in 

 English &quot;yeast.&quot; Although the cells of ordinary yeast and those of the Mycoderma vim, 

 aceti, or lactis, differ in shape and size, it is supposed that these variations are due to the 

 character of the fluids by which they are nourished, and that they are all really derived 

 from the same source, namely, the ordinary molds. Common brewers yeast (Oryptococ- 

 cus cerevisii) is now thought to be not a distinct species of plant, but merely a stage of 

 development of several different - genera of fungi, such as penicillium, aspergillus, mucor, 

 and perhaps several others. And the same is probably true of the other mycoderms. 



When organic substances rich in nitrogen decompose, the action is termed putrefac 

 tion; and in all such, when examined with a sufficiently high magnifying power, there will 

 be found little molecules, either single or in chains of from two to six, and minute color 

 less rods, single or in chains of two or three, straight or spirally twisted, rigid or flexible. 

 All of these may be at rest or in motion; if the latter, it may be a vibrating, trembling 

 motion, without change of place, or a direct propulsion through the fluid. These minute 

 organisms have been successively considered as animals, as alga? or water plants, and as 

 fungi. The globular molecules are termed monads, and more recently micrococcus. The 

 rods have received many names, but are usually known as bacteria. The tendency of 

 investigators of this subject is to consider these monads and bacteria as the mycoderms of 

 the putrefactive fermentation, and to suppose that they also are but one form of develop 

 ment of penicillium and other common molds. Mrs. J. Luders asserts that she has seen 

 the bacteria emerge from spores of penicillium placed in meat juice, and the production 

 of yeast by adding putrefying fluids to saccharine solutions has been repeatedly accom 

 plished. 



We have performed some experiments on this subject which may perhaps be of 

 interest. 



Our aim was to develop in a saccharine solution an unmistakable yeast cell, with its 

 attendant special form of fermentation, from a vibrio or bacterium contained in a putrefy 

 ing fluid; and the practical problem was to devise some means whereby the putrid fluid 

 might be added to the sugar solution, without at the same time any yeast cells, which it 

 might accidentally contain, also passing into the solution and so vitiating the result. To 

 accomplish this end we availed ourselves of the different behavior of yeast cells on the 

 one hand and the various cryptogamic organisms of putrid fluids on the other, in respect 

 to their ability to pass through certain tissues. Now, bacteria, vibriones, and molecules, 

 cither single or in chains, (Monas, Microzymas, Micrococcus, Lcptothrix, Zooglca, and 

 Schizomycetes, of various authors,) will readily pass through thoroughly moistened filtering 



