ANAEROBIC RESPIRATION 53 



in the number of yeast cells is thereby made possible with a 

 deficiency of oxygen. Now Pasteur assumed that analogous 

 phenomena also proceed in other plants with a deficiency 

 of oxygen, although less markedly. The experimental proof of 

 this assumption showed in fact that the primary products of 

 alcoholic fermentation/ i.e. ethyl alcohol and carbon dioxide, 

 are also formed in seed-plants under anaerobic conditions. 



It is easy to understand why the systematic investigations 

 of Pasteur and his students were the first to receive attention, 

 although the liberation of COo in the absence of oxygen had 

 already been estabhshed for various plant organs by numerous 

 investigators, as e.g. by Rollo,^ de SaussurerDumont.^Berard,^ 

 and Dobereiner.^ However, it was left uncertain whether the 

 formation of CO2 should be regarded at all as a vital phenome- 

 non. Especially since Pasteur was the first to speak of an alco- 

 holic fermentation of seed-plants and thus labelled the anaerobic 

 formation of COo as a strictly vital process, he is really to be 

 called the founder of the doctrine of the anaerobic respiration 

 of plants. Pasteur also studied various molds with a deficiency 

 of oxygen and established the important fact that there are 

 various transition stages between yeast and strictly aerobic 

 fungi {e.g. Penicilliu7n glaucum). Thus mucors in part repre- 

 sent strictly aerobic molds but in part are organisms of fermen- 

 tation. According to Pasteur's statements, even strictly aerobic 

 molds form small quantities of COo and alcohol in the 

 absence of oxygen. 



The investigations of Pasteur were not known to Bohm^ when 

 he rediscovered anaerobic production of COo by green parts of 

 plants, but he drew no theoretical conclusions therefrom. 

 The formation of alcohol also escaped his notice. The later 



1 RoUo. Ann. de chim. 25: 42. 1798. 



- de Saussure. Rech. chim. sur la vegetation. 1804. 



* Dumont. Neues Jour. f. Pharmaz. 3: 568. 1819. 



* Berard. Ann. de chim. et de physique. Vol. 16. 1821. 

 5 Dobereiner. Ann. d. Physik. 72 : 430. 1822. 



« Bohm. Sitzungsber. d. Akad. d. Wiss. Wien (I) 67: 219. 1873. 



"" For a concise statement of the nature of alcoholic fermentation see Palladin's 

 Plant Physiology. 3rd. Eng. ed., pp. 204-211, where references to the original 

 papers are also given. For recent theory see Warden, C. C. .\mer. Jour. Physiol. 

 57:454-469. 1921. F. F. Nord (Chem. Rev. 3:41-79. 1926) has recently 

 summarized our knowledge of the chemical processes in all fermentations. — Ed. 



