THE BIOCHEMISTRY OF MICRO-ORGANISMS; 

 AN APPROACH TO GENERAL AND COM- 

 PARATIVE BIOCHEMISTRY 



By C. B. VAN NIEL 



HOPKINS MARINE STATION OF STANFORD UNIVERSITY, PACIFIC GROVE, CALIF. 



Theodor Schwann (1837), the founder 

 or co-founder of the cell theory, was, with 

 Cagniard Latour and Kiitzing, among the 

 first to attribute to a micro-organism, the 

 yeast, the vital function of producing alco- 

 holic fermentation. It seems far from ex- 

 cluded that his studies on the morphology 

 and development of this unicellular organ- 

 ism were of decisive importance in prepar- 

 ing his mind for the concept that there 

 exists but one general mode of formation 

 of all organized beings, which is the forma- 

 tion of cells as constitutive units^ (Schwann 

 1839, p. 197). In his discussion of the 

 forces through which constituents of the 

 environment and of the cells themselves 

 are changed, he mentions the process of 

 alcoholic fermentation as a specific and 

 clear-cut example of the idea that such 

 forces are attributes of the cells only.^ 

 Such a connection would add another 



1 ' ' Die Entwicklung des Satzes, dass es ein all- 

 gemeines Bildungsprinzip fiir alle organischen Pro- 

 duktionen gibt, und dass die Zellenbildung jenes 

 Prinzip ist, und die aus diesem Satze hervorge- 

 henden Folgerungen kann man mit dem Namen der 

 Zellentheorie im weitern Sinne belegen. " 



2 ' ' Ich habe es nicht vermeiden mogen, die 

 Gahrung als Beispiel anzufiihren, da sie die am 

 genauesten bekannte Wirkung der Zellen ist, und 

 am einfachsten den Prozess darstellt, wie er sich 

 im lebenden Korper an jeder Zelle wiederholt. Fiir 

 diejenigen iibrigens, welche die von Cagniard-La- 

 tour und von mir aufgstellte Tlieorie der Gahrung 

 noch nicht anerkennen, kann die Entwicklung aller 

 einfachen Zellen, namentlich der Sporen, als Bei- 

 spiel dienen, und es soil im Text aus der Gahrung 

 kein Schluss gezogen werden, der sich nicht auch 

 aus der Entwicklung anderer einfacher und ausser 

 Zusammenhang mit einem anderen Organismus 

 sich entwickelnder Zellen, namentlich der Sporen 

 niederer Pflanzen ziehen lasst. . . , iibrigens diirf te 

 die vorliegende Untersuchung iiber den Bildungs- 

 prozess der Organismcn viellcicht Einiges dazu 

 beitragen, auch der f raglichen Theorie der Gahrung 

 bei den Chemikern mehr Eingang zu verschaffen. " 

 (p. 234.) 



case to the already large number of 

 fundamental concepts which have resulted 

 from the study of micro-organisms and 

 their activities. I will discuss some of 

 these concepts and generalizations primar- 

 ily from the point of view of the biochemist. 



No one will challenge the statement that 

 all living organisms have some general 

 characteristics in common by which they 

 can be recognized as living. Even though 

 it may be difficult to decide upon the true 

 nature of these characters — and the some- 

 times almost violent controversies on the 

 possible living nature of bacteriophage and 

 virus during the past fifteen years have 

 shown this sufficiently ! — it may still be in- 

 ferred that the common characteristics in 

 their most elementary form will be met 

 with in the simplest of living organisms, 

 and it is not difficult to agree with the 

 remark of Rahn (1932) : 



I believe that some of the principles of biology 

 can be found and studied only with the simplest 

 forms of life, and that general physiology has 

 much to learn from the physiology of bacteria. 



This has already happened in no small 

 measure, and the prospects for continued 

 contributions of a fundamental nature to 

 this field of endeavor by studies on micro- 

 bial physiology are as good as ever. 



The first important contribution to 

 physiology was contained in observations 

 which were made at a time when no one 

 could yet realize its vast consequences. In 

 his multifarious studies on microscopic 

 forms of life, Antonie van Leeuwenhoek 

 discovered, in 1680, the existence of organ- 

 isms living in the absence of air (Beijerinck 

 1913, 1921; Dobell 1932). Only after the 

 discovery of oxygen, at the end of the 

 eighteenth century, when Lavoisier stressed 



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