SPONTANEOUS GENERATION. 595 



reference to the phenomena of infectious disease, distin- 

 guishing arguments based on analogy which, however, are 

 terribly strong from those basevl on actual observation. I 

 should have liked to follow up the account I have already 

 given* of the truly excellent researches of a young and an 

 unknown German physician named Koch, on splenic fever, 

 by an account of what Pasteur has recently done with 

 reference to the same subject. Here we have before us a 

 living contagium of the most deadly power, which we can 

 follow from the beginning to the end of its life cycle, f 

 We find it in the blood or spleen of a smitten animal in 

 the state say of short, motionless rods. When these rods 

 are placed in a nutritive liquid on the warm stage of the 

 microscope, we soon see them lengthening into filaments 

 which lie, in some cases, side by side, forming in others 

 graceful loops, or becoming coiled into knots of a com- 

 plexity not to be unraveled. We finally see those filaments 

 resolving themselves into innumerable spores, each with 

 death potentially housed within it, yet not to be distin- 

 guished microscopically from the harmless germs of Bacillus 

 subtilis. The bacterium of splenic fever is called Bacillus 

 anthracis. This formidable organism was shown to me by 

 M. Pasteur in Paris last July. His recent investigations 

 regarding the part it plays pathologically certainly rank 

 among the most remarkable labors of that remarkable 

 man. Observer after observer had strayed and fallen 

 in this laud of pitfalls, a multitude of opposing conclu- 

 sions and mutually destructive theories being the 

 result. In association with a younger physiological 

 colleague, M. Joubert, Pasteur struck in amid the 

 chaos, and soon reduced it to harmony. They proved, 

 among other things, that in cases where previous observers 

 in France had supposed themselves to be dealing solely 

 with splenic fever, another equally virulent factor was 

 simultaneously active. Splenic fever was often over- 

 mastered by septicaemia, and results due solely to the latter 

 had been frequently made the ground of pathological in- 

 ferences regarding the character and cause of the former. 



* "Fortnightly Review," November, 1876, see article "Fermenta- 

 tion " 



f Dallinger and Drysdale bad previously shown what skill and 

 patience can accomplish, by their admirable observations on the life 

 history of the monads. 



