14 THE GERM THEORY OF DISEASE. 



FIRST DEFINITE ANNOUNCEMENT. 



The first definite announcement of a belief that disease is 

 caused by organic germs, that I have found, was in the time 

 of the Roman Empire. 



De-re-Rustica, Varro and Columella, refer the origin of 

 malarious fevers to the entrance of low organisms into the 

 body. But they seem not to have given the special observa- 

 tions upon which their conclusions were founded. All along 

 down the centuries, the idea was frequently expressed that the 

 plague of the day was caused by minute organisms. 



This doctrine, however, obtained wide recognition when 

 some sort of basis for such theories was furnished by the 

 microscopic demonstration of very minute living organisms, 

 invisible to the naked eye. Especially after the discovery of 

 the spermatozoa by Leuwenhoeck in 1677. These were then, 

 and for years afterwards, supposed to be real animals. It 

 having now been demonstrated, apparently, that real animals 

 were living in the bodies of men, the doctrine that diseases 

 were caused by minute organisms spread far and wide. Among 

 the best known advocates of this theory were Kirchen, Lancici, 

 Valisneri, Raumum, and Linne. But even those who best 

 understood the theory never reached anything more than 

 rough conceptions ; while many lost themselves in wild ex- 

 aggerations. The animals causing disease were described as 

 flying about in the air, something like swarms of insects, with 

 crooked bills and sharp claws ; and one writer proposed to 

 destroy them during epidemics by the blowing of horns and 

 the firing of cannon. We can readily conceive that such 

 fantasies would bring down ridicule upon the whole theory ; 

 and in time these wild notions were dissipated and the germ 

 theory slept. 



