238 ANNUAL OF SCIENTIFIC DISCOVERY. 



he began to perceive an inevitable coincidence between the infuso- 

 rials and the production of this acid ; a circumstance which he had 

 previously attributed to the peculiar fitness of butyric acid to the 

 life of these animalcules. After this observation, however, a great 

 number of experiments convinced him that the transformation of 

 sugar, of mannite, and of lactic acid, into butyric acid, was due ex- 

 clusively to these infusorials ; and that they must be regarded as the 

 true butyric ferment. 



M. Pasteur describes these animals as small cylindrical bodies, 

 rounded at their extremities, generally straight, and connected to- 

 gether in chains of two, three, or four links each, sometimes more. 

 Their length does not exceed the fifteen thousandth part of a mil- 

 limeter ! These diminutive creatures advance with a creeping mo- 

 tion, their body remaining nearly rigid, or at best experiencing but 

 slight undulations. They are often bent at one or both of their ex- 

 tremities, but this seldom happens in their youth. They are fissipa- 

 rous, that is, they multiply by separation, one link after another 

 dropping off from the parent animal, and becoming a parent of oth- 

 ers itself. 



These infusorials may be grown or increased as we grow yeast of 

 beer. They multiply themselves if the medium is appropriate to 

 their nourishment. It is observed also that in a liquid only contain- 

 ing sugar, ammonia, and the phosphates, crystalline, so to say, min- 

 eral substances, they reproduce themselves correlatively to the buty- 

 ric fermentation, which soon becomes very manifest. The weight 

 of the amount formed is notable, although always small, compared to 

 the total quantity of butyric acid produced. 



The existence of infusorials possessing the character of ferments 

 is a fact sufficiently worthy of attention ; but it is accompanied in 

 this case by a singular peculiarity. It is, that these animalcules live 

 and multiply to infinity without being furnished with the least por- 

 tion of air or free oxygen. M. Pasteur has demonstrated this curious 

 fact by numerous experiments, which have proved satisfactory to 

 those members of the Academy who witnessed them. But he goes 

 further. He states that these infusorials not only live without air, 

 but that air kills them. If a current of carbonic acid be passed 

 through the liquid in which these animals are living and generating, 

 they are not in the least affected ; but if a current of air be substi- 

 tuted for the carbonic acid, they all perish within a couple of hours, 

 and the butyric fermentation which depends on their existence is at 

 the same time arrested. We obtain, therefore, this double proposi- 

 tion : 1st. The butyric ferment is an infusorial animal. 2d. This 

 infusorial lives without free oxygen. This appears to be the first 

 example of an animal ferment, and also of an animal living without 

 oxygen. 



PRODUCTION AND PREVENTION OF MALARIA. 



At a recent meeting of the Manchester Literary and Philosophical 

 Society, a paper was read by Dr. Angus Smith, " On the Produc- 

 tion and Prevention of Malaria." 



The author did not pretend to enter on the whole subject, but to 

 give a few observations which he considered fitted for its illustration. 



