DR. SALMON. 51 



expressed by saying that the bacteria, per se, are unable to 

 grow in normal serum, and can only develop in the liquid 

 when vitiated, whether by the addition of water or by the 

 action of small quantities of the acrid products of decompo- 

 sition. 



" Or, again, it seems to me conceivable that the normal 

 serum may oppose an insuperable obstacle to the nutritive 

 attractions of an individual bacterium, but that this may be 

 overcome by the associated attractions of several of the 

 organisms in close proximity, after the analogy of the more 

 energetic operation of a concentrated solution of a chem- 

 ical reagent. But whatever be the explanation the fact re- 

 mains." 



I give the first statement of Mr. Lister as the strongest 

 statement of the view against the primary causative effects of 

 bacteria that I have seen, while I regard the second as 

 approaching very nearly a true explanation of the facts in the 

 case. I will refer to this again. 



One fact Mr. Lister thinks demonstrated beyond question. 

 Pure blood resists decomposition under circumstances in which 

 very many other substances decompose, and that a blood clot is 

 a much better antiseptic dressing than was supposed. Most 

 forms of bacteria must be grouped together in some numbers 

 before they can live and grow in blood ; while a single bac- 

 terium lactis detached from others and washed with purified 

 water will be'sufficient to start decomposition in milk. 



DE. SALMON. 



The idea that pathogenic bacteria must be grouped together 

 in considerable numbers in order to grow in the blood or 

 tissue of animals, has recently been strongly confirmed by the 

 experiments of Dr. Salmon (see Medical Record, April 7th, 

 1883), in his experiments with u dilutions" of the organisms 



