INTIIAMOLECULAH KKSPIKATION. 79 



respinitioii are the eurbohydi-iites, tmd in fact, priiiiurily aud 

 diiertlv, oiil\ reitiiiii kinds of Kugiir, wliich are dee<im|>OKed in 

 siu'li a iJiaiiiiiM- as to fiiinish, in addition to cailMin ilioxide, a 

 residual product poorer in oxygen. This product, however, is 

 1)V no means a uniform entitv, hut consists of a mixture of 

 several suhstances, alcohol beinj; an invariable constituent. In 

 lii^rher plants the enerj^y with which carbon dioxide is liberated 

 during intnunolecular respiration is not infre<piently on a jwir 

 with that exhibited in normal respiratiiin, and indeed is in some 

 cases even superior; though, as has been shown by WiiJ^oN (I.), 

 it is always inferior thoret<j in the case of fungi. All the 

 preliminary conditions nece-s-sjiry to the inception of such a 

 procress of decomposition are present in the case of sweet (germ- 

 free) fruits that are kept, uninjured, for a long time out of 

 contiict with air; and. in fact, it was in connection with such 

 fruits that the first observations on intnimolecular respiration 

 were made, early in the nineteenth ci-ntuiy. At that time 

 the phenomenon was known as the autofermentation of fniit 

 (see ^ 20). The extensive literatuie of this >ubject has been 

 collected in a meritorious treatise by C. CJekuek (1.). It is not 

 within the province of the piesent work to go more closely 

 into the botanici>-physiological aspect of this phenomenon ; and 

 besides it will be found thoroughly leported in the above- 

 mentioned Ihindliooli of Pfelfer's, by all who are interested in 

 the matter. 



The tirst observation of iutiamolecular respinition in fungi 

 was that of Bail (1.), who, in 1857. .showed that the mycelium 

 of certain (unspecified) Muciirf, when kept submerged in a 

 sjicchariiie licpjid ami out of contact with air, a-s-sumes an unusual 

 foiMi (si'f ,^ 219), and in.stead of consuming the sugar to carbon 

 dit)xide, as it does in presence of air. converts the same in such 

 a manner as to produce alcohol. This new fact was .seized U|H)n 

 by PastEIK (11.), who endeavoured to utili>e it as a pillar of 

 support for his novel theory of fermentJition. This we have 

 already referred to in ^ 16 and <$ 113, mentioning at the time 

 that it is not universiilly applicable. In fact it is only uncon- 

 ditionally true in the ca.se of a single group of phenomena, 

 namely those produced by strictly ana-robic agents, the butyric- 

 acid bacteria in particular. On the other hand, <lifliculties aie 

 encountered in the case of alcoholic fermentation, N.KiiEi.i (III.) 

 having shown that this fermentation . when excited bv veast-s, 

 proceeds just as well, or even better, in presence of free oxygen lu* 

 when that gas is excluded — a result entirely opposinl to the tluH)rv 

 in question. Nevertlu'le.ss, the ob.scivati»)ns of l'a>teur and his 

 predecessors, concerning the prcnluction of alcohol by Miirontf 

 under the specified conditions, remain unimpeached ; only, this 

 formation of alcohol must not be regarded as perfectly identical 

 in nature with the alcoholic fermentation excited bv veasts. 



