NOTES AND MEMORANDA. 



405 



In comparing the results stated in the above table, the 

 substances can be classed under four distinct heads, viz. 

 those which prevent the development of protoplasmic and 

 fungus life ; those which prevent the production of vibrio 

 life, but do not prevent the appearance of fungus life ', those 

 Avhich permit the production of vibrio life, but prevent the 

 appearance of fungus life ; and those which do not prevent 

 the appearance of either protoplasmic or fungus life. 



The first class contains only two substances — carbolic and 

 cresylic acids. 



In the second class, also, there are only two compounds — 

 chloride of zinc and bichloride of mercury. 



In the third class there are five substances — lime, sulphate 

 of quinine, pepper, turpentine, and prussic acid. 



In the fourth class is included the remaining twenty-five 

 substances. 



The acids, while not preventing the production of vibrio 

 life, have a marked tendency to promote the groAvth of 

 fungus life. This is especially noticeable in the case of 

 sulphuric and acetic acids. 



Alkalies, on the contrary, are not favorable to the pro- 

 duction of fungus life, but promote the development of 

 vibrios. 



The chlorides of zinc and mercury, while completely pre- 

 venting the development of animalcules, do not entirely 

 prevent fungus life; but I would call special attention to 

 the interesting and unexpected results obtained in the cases 

 of chlorine and bleaching-powder. When used in the pro- 



