HOMO MILITANS 



When, in 1901, the 'Hollandsche Maatschappij der Wetenschappen' 

 decided henceforth to include a special lecture on some scientific subject 

 in the programme of its general meetings, it was also stipulated that 

 this should be allocated in turn to different branches of science. This 

 implies that the member whose privilege it is to deliver one of the an- 

 nual lectures faces a grave responsibility with respect to the particular 

 branch he represents. This is so because the manner in which he ful- 

 fills his task cannot fail to influence the appreciation of his specialty on 

 the part of the directors and fellow members of the society. As a micro- 

 biologist it is therefore my duty to evoke in my audience, largely com- 

 posed of laymen in the field, an interest in our knowledge of the micro- 

 bial world. Hence it has seemed to me that I should attempt to make 

 my audience 'microbe-minded , , at least for the time span that will 

 elapse till our next annual meeting, when new impressions are apt to 

 displace the present ones. Consequently I decided to elaborate the 

 thesis that, even though most of you have thus far benefited from neg- 

 lecting the microbial world, the microbes themselves are not always 

 prepared to neglect mankind. In other words, it seemed an attractive 

 task to discuss briefly the man-microbe relationship. 



On further consideration I soon realized, however, that within the 

 prescribed time limit it is not feasible to review this relationship from 

 all angles, and that I would have to restrict myself to a few aspects. 

 I might, for example, have discussed the microbes as benefactors of 

 mankind, and depicted the disconsolate horrors of human life on a 

 microbe-less world. But rather than doing this I have decided to di- 

 rect your attention to the far less numerous microbes inimical to man. 

 On the one hand it are particularly these microbes that have left their 

 direct imprint on the history of mankind ; on the other hand this topic 

 seemed to offer an opportunity to elicit your interest in man's incessant 

 fight against his assailants from among the realm of invisible life. 



It was during this phase of my deliberations that I decided to use 

 'Homo militans' as the title of my lecture. Soon afterwards I learned 



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