C. A. WATKINS ON YEAST AND OTHER FERMENTS. 167 



complex action of the growth of the fungus on the matters in solu- 

 tion ; but the exact chemical operations of this vegetation are 

 unknown. 



Since writing the above, my attention has been called to some 

 observations on this plant by Mr. Slack, (Vol. V., p 2), and pub- 

 lished in the " Microscopical Transactions." He states — and I have 

 no doubt of the truth of the assertion — that, " If some of the 

 gelatinous portion of the plant be examined with high powers, it 

 will be found to contain millions of minute bodies, resembling 

 bacteria, some of them not exceding 16 o 00 of an inch in length. 



I have recently examined a dilute solution of alcohol, which is 

 being converted into vinegar, and find these bacteria in abundance. 

 They may be seen distinctly when magnified 250 diameters, though 

 a high power must be used to resolve their structure. 



The study of these minute organisms, though very uninviting to 

 the general microscopist, would richly reward any patient investi- 

 gator — for until we know more of the chemical processes which 

 take place in and through them, the subject of putrefactive decom- 

 position must remain a blank, as it is at present. 



The vinegar plant and yeast are said to be different conditions 

 of the same vegetation ; the Brothers Tulasne have shewn us that 

 these lower species of vegetation pass through various phases during 

 their growth, each having previously been considered as a distinct 

 plant ; and I see no reason why these minute organisms should not 

 produce different chemical combinations at the different stages of 

 their development, since we see, in the higher order of certain 

 plants, that some of their chemical processes are reversed at 

 points of their existence, namely, during germination, flowering, 

 and the ripening of the fruit, when they absorb oxygen and give 

 off carbonic acid to the atmosphere. 



In conclusion, allow me to observe, that I am fully aware of 

 having written a paper with a very slender knowledge of the micro- 

 scopic organisms, whose chemical operations I have discussed; 

 therefore, I hope those parts which I have left in darkness will 

 now receive the light of your experience and knowledge as micro - 

 scopists. I am very anxious to obtain information concerning the 

 part which those minute vibriones and bacteria play in nature's 

 economy, for there can be no doubt that those remarkable bodies, 

 appearing everywhere, and springing into active existence almost 

 at a moment's notice, must perform some important part in many 

 of the changes which surround us. 



