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of bacteria are worthy of consideration perhaps, though 

 not because of their intrinsic weight. To some it is in- 

 credible that bacteria should harm us, since we live in 

 health though surrounded by them eating, drinking, 

 and breathing them. If it be remembered, however, 

 that the name bacteria is merely a convenience for 

 designating organisms of widely different functions, 

 this argument seems less formidable. On the same 

 principle it might be asserted that all mammalia are 

 harmless because we come into daily contact with 

 sheep, cattle, horses without injury. The diversity in 

 function, food, etc., among the microscopic beings is 

 not less marked than among the larger organisms : 

 there are bacteria, and bacteria. It is surprising that 

 Mr. Cheyne, in his admirable work on antiseptic sur- 

 gery, falls into a similar error. He admits that bac- 

 teria are not infrequently found under Mr. Lister's 

 own dressings ; that sometimes the course of the wound 

 appears thereby unaffected, .while at other times he 

 thinks he has observed that the wounds heal less kindly. 

 He consoles himself, however, with the reflection that 

 these are " only micrococci." He seems to forget that 

 several species of micrococci are distinguishable in form, 

 size, color, and function from one another and from all 

 others. The fact that certain micrococci found during 

 different diseases are morphologically indistinguishable 

 from others found under Mr. Lister's dressings, does not 

 justify the assumption that all are functionally identical. 

 If Mr. Cheyne were requested to swallow some pills, he 

 would probably inquire as to their contents before com- 

 plying, and would not be satisfied with the assurance 

 that they were " only pills." Yet we have every reason 

 for asserting that the minute globules known collectively 

 as micrococci present differences as great as the larger 

 globules designated, for convenience, pills. When we 

 reflect that the active agents in the induction of pyaemia 

 are micrococci ; that the organisms found in malignant 

 diphtheria are micrococci, we must protest against Mr. 

 Cheyne' s promiscuous ascription of benign qualities to 



