THE ENVOY Sle 
bodies of living animals—including man: but he never in his 
writings suggested, so far as I am aware, that his discovery of 
such “animalcules” threw any light upon the aetiology of 
morbid infections or furnished, for the first time, an objective 
basis for the old speculations regarding the existence of 
“living germs” of diseases—seminaria morborum, contagium 
vivum, contagium animatum, and the like. Yet this applica- 
tion of his findings was immediately made by others. Within 
a few months of the appearance of his Letter 18, announcing 
the discovery of the “little animals” in all manner of liquids, 
we find “an observing person in the country” writing to the 
editor of the Philosophical Transactions as follows': ‘‘ Mr. 
Leewenhoecks Microscopical Discoveries are exceeding curious, 
and may prompt us to suspect, that our Air is also vermicu- 
lated, and perhaps most of all in long Calms, long-lasting 
Eastern Winds, or much moisture in Spring-time, and in 
seasons of general Infections of Men or Animals.” 
As soon as this possible connexion between demonstrable 
“animalcules” and hypothetic infectious “germs” was 
suggested, it became almost commonplace : its theoretical im- 
plications and its obvious practical applications were henceforth 
recognized. Yet nobody made any real use of them during 
the next century anda half. Mankind possessed the necessary 
data, and was inspired—as usual—by the appropriate ideas : 
but the course of history has shown that both knowledge 
and notions arrived prematurely. We should not blame 
Leeuwenhoek, therefore, for making discoveries before they 
could be appreciated properly either by himself or by the world 
at large. Rather should we censure, I think, those modern 
writers who do not take his work into consideration when 
discussing present-day problems. ‘To me it is incomprehensible 
how one author in my lifetime could have defended a thesis on 
Parasitology in the XVI and XVII Centuries,’ and another 
could have written a book on The Discovery of the Microbic 
1 See Anonymus (1677). Cf. also the words of Slare (1683), quoted 
already on p. 230. 
2 Rémignard (1902). This dissertation—approved by the great Raphael 
Blanchard—contains only two ridiculous references to L. The first (p. 55) 
merely alludes to the fact that he did not discover Demodex, while the 
second (p. 63) informs us that he believed in the spontaneous generation 
of frogs. 
