like to bring it home to y.mr intelligence by a single trust- 

 worthy illustration. In lS.~>o. two distinguished |-' 

 observer-. MM. 1 ) .ivainne :iml liayer, noticed in the : 

 of animals which had died of the virulent disease called 

 " fever, small microscopic organisms resembling 

 transparent rods, but neither of them at that tiin< 



ignilicancr to the .n. In 1 *'!. 1' 



published a nicnioir on the fermentation of but\ii< 

 wherein he 'described the organism which provoked it; ami 

 :mg this memoir it occurred to Davainne that 

 splenic; fever might he a case of fermentation net up within 

 tlie animal htly, by the organisms which had been observed 

 by him ami Raver. This idea has been placed beyond all 

 don lt by subsequent research. 



Observations of the highest importance have also been 

 made on splenic fever by Pollemler and Brauell. Two 

 years ago. Or. llm-don Sanderson gave us a \ 

 account of what wus known up to that time of this dis- 

 order. With regard to the permanence of the contagium. 

 it had been proved to bang for years about localities where 

 it had once prevailed; and this seemed to show that the 

 rod-like organisms could not constitute the contagimn, 

 ;se their infective power was found to vanish in a fe\\ 



P.nt other facts established an intimate conn* 

 between the organisms and the disease, so that a review of 

 all the facts caused Dr. Sanderson to conclude that the 

 contagium existed in two distinct forms: the one " fugitive " 

 and visible as transparent rods; the other permanent but 

 " latent,'' and not yet brought within the grasp of the 

 mieroscope. 



At the time that Dr. Sanderson was writing this r ; 



an physician, named Koch,* occupied with 



the duties of his prolVs>ion \\\ an oioeure country district. 



was already at work, applying, during bis spare time, 



aland ingenious devices to the investigation 



of splenic fever. lie Mndied the habits of the rod-like 



. and found the aqueous humor of an ox's eye to 



ticiilaily suitable for their nutrition. With a "drop 



of ill. -IP Minor he mixed the tiniest speck of a 



liquid containing tho rods, placed the drop under ins 



* Thi. I Miere. wan the firat reference to the reaearehes of 



in this country. !?. 



