INTRODUCTION. 23 



side, he arranged a series of empty test-tubes in the 

 bottom and a pipette in the top, so that when desired 

 the tubes, one by one, could be filled through it. The 

 chamber was first submitted to an optical test to deter- 

 mine the purity of its atmosphere, and was allowed to 

 stand undisturbed and unused until a powerful ray of 

 light passed through the side windows failed to reflect 

 rays from suspended particles of dust when viewed from 

 the front. When the dust had settled so as to allow the 

 optical test of its purity, the tubes were filled with urine, 

 beef-broth, and a variety of animal and vegetable broths, 

 boiled by submergence in a pan of hot brine; the tubes 

 were then allowed to remain undisturbed for days, weeks, 

 or months. In nearly every case life failed to develop 

 after the purity of the atmosphere was established. 



In 1873, Obermeier observed that actively motile, flex- 

 ible spiral organisms were present in large numbers in 

 the blood of patients in the febrile stages of relapsing 

 fever. 



Thus evidence slowly accumulated to establish the 

 theory for which Henle had labored as early as 1821, that 

 for many diseases at least there was a distinct and specific 

 contagium vivum, and the U GERM THEORY" was pro- 

 pounded. 



Is it not strange that the very idea which was to be the 

 outcome of all this investigation and discussion an idea 

 which would form a new era in scientific medicine and 

 become a fundamental principle of pathology was one 

 which had been conceived and taught by a philosopher 

 who lived nearly two thousand years ago? Among the 

 numerous works of Varro l is one entitled Rerum Rusti- 

 cantm libri tres, from which the following is quoted : 

 "Animadvertendum etiam, si qua erunt loca palustria 

 quod crescunt animalia quaedam minuta, quae non pos- 

 sunt oculi consequi et per ae'ra intus in corpus per os ac 

 nares perveniunt atque efficiunt difficilis morbus " (L, 

 xii. 2)." It is also to be noticed, if there be any marshy 



1 Univ. Med. Mag., vol. iii., No. 3, Dec., 1890, p. 152. 



