284 CONTAGIOUS DISEASES. 



the conclusions of Pasteur. In a series of experiments Bert 

 submitted anthrax blood to the action of considerably com- 

 pressed oxygen, and found the bacilli had disappeared, killed by 

 the oxygen, and yet the blood retained its virulence, for it 

 killed rabbits, guinea-pigs, and dogs inoculated with it ; and in 

 another series of experiments Bert took anthrax blood contain- 

 ing bacilli, and added drop by drop of absolute alcohol to it, 

 until a precipitate was formed, and which was dried in vacuum. 

 This dried powder was injected under the skin, and it killed a 

 rabbit, a guinea-pig, and even a dog. 



If this alcoholized precipitate be dissolved in water and 

 filtered, the filtrate is still virulent. If alcohol is again added 

 to it, it forms a flocculent matter, which is deposited at the 

 bottom of the vessel. Collected on a filter and dried, this 

 precipitate is still toxic. It would therefore appear that the 

 active or virulent element of anthrax resists absolute alcohol, 

 and that it resists oxygen, and that it is precipitated by alcohol 

 and soluble in water. It behaves itself something like diastase, 

 except that, whatever may be its nature, it can reproduce itself 

 to an indefinite extent ; while it is asserted by some authorities 

 that diastase cannot reproduce itself. 



Putting aside the conclusions of Colin — that the bacilli are 

 simple transformation of the blood-corpuscles — we are left 

 between two sets of conclusions. Those of Koch and others 

 point to splenic fever being due to a minute organism possessing 

 wonderful powers of resistance and reproduction ; Bert's to 

 something independent of the presence or absence of animal or 

 vegetable organisms — a ptomaine — which resist the action of 

 compressed oxygen and absolute alcohol, and which would, he 

 asserts, kill everything possessing life : this something he is of 

 opinion is a substance analogous to diastase. 



Blood containing bacilli, if dried in very thin layers, by being 

 exposed to the air in a shady place, was found by Koch to lose 

 its virulence and its power of developing elongated fibres after 

 twelve to thirty hours. Thicker layers retained their powers 

 for two or three weeks ; and some still thicker for four or five 

 weeks. After a longer time they were never capable of pro- 

 ducing the disease. 



Koch also found that if the bacilli were deprived of air they 

 soon died. 



