MICROBE AND LIFE 



dioxide. Already at an early date the respiratory process of man and 

 animals has been marked out as such a source of carbon dioxide. A 

 century ago Pasteur emphasized that the conversion into carbon diox- 

 ide of that part of dead vegetable matter that is not used as animal 

 food proceeds under the influence of the microbial world. Tersely he 

 formulated this idea in the statement: 'C'est encore la vie qui preside 

 au travail de la mort'. Our late fellow-member, Eugene Dubois, who 

 so often spoke in this very hall, was probably the first to venture an 

 estimate of the extent to which animals and microbes, respectively, 

 participate in this carbon dioxide production. Dubois concluded that 

 the former is of an order of magnitude of only 2 per cent. And because 

 during the historical era an equilibrium between production and 

 utilization has evidently existed, this implies that the remaining 98 

 per cent must largely be ascribed to microbial activity. Even though 

 these figures may be in need of some correction, this situation entails 

 the inevitable consequence that, as far as vital processes are concerned, 

 the bulk of matter of microbial origin must exceed that of the animal 

 kingdom by many times. Thus the microbiologist is imbued with the 

 notion that perhaps more than one-half of life, i.e., of the totality of 

 vital phenomena, escapes the attention of the unsuspecting observer. 

 This might also be paraphrased as follows : the major part of life on 

 earth has, so to speak, 'gone underground', implying that to the micro- 

 biologist has been assigned the task of studying the macromoiety of 

 life. 



Another characteristic feature of life that forces itself particularly 

 on the microbiologist is the indissoluble interrelatedness of all living 

 creatures which is, for example, manifest in the indispensability of the 

 microbial world for plants and animals. If someone were to possess 

 a magic force with which at one fell swoop he could destroy exclu- 

 sively the single-celled forms of life, there would be hardly any im- 

 mediately apparent changes. But very soon disastrous consequences 

 would emerge. All those areas where plant life flourishes, all the 

 woods, meadows, etc., would be changed into arid regions in the 

 course of a few years. On an earth where Homo sapiens had not yet 

 made his appearance this would inevitably imply an early cessation 

 of animal life as well. Only the circumstance that in a later phase of 

 terrestrial evolution the human intellect must also be taken into ac- 

 count forces me to make some reservations concerning the present. 



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