1872.] Dr. F. Crace-Calvert on Arresting Putrefaction, 191 



plasmic nor fungus-life appeared during the time the experiments were 

 continued. 



Another substance, arsenious acid, also presented a marked difference in 

 its action in the two solutions ; for although with albumen twenty-two days 

 elapsed before vibrios were present, and eighteen before fungi, with gelatine 

 animal life appeared after two days, and at no time did any fungi exist. 

 The effects of the other substances with gelatine were so similar to those 

 with albumen, that it is unnecessary to state them here. 



III. " On the Relative Power of Various Substances in arresting 

 Putrefaction and the Development of Protoplasmic and Fungus- 

 Life." By Dr. F. Crace-Calvert, F.R.S. Received February 

 22, 1872. 



(Abstract.) 



This series of experiments was undertaken as being complementary to 

 those described in my last paper, and consisted in adding to a solution 

 of albumen, swarming with microscopic life, one-thousandth part of the sub- 

 stances already enumerated in that paper, and examining the results pro- 

 duced immediately after the addition of the substances, and after one, six, 

 and sixteen days ; but in this abstract only the results obtained in the first 

 and last cases will be noticed. 



The solutions were placed in test-tubes similar to those described in my 

 last paper. 



The experiments were begun on the 20th Sept. 1871, the solutions being 

 kept at a temperature of 15°-1 8° C. 



In the standard solution the amount of life and putrescence increased 

 during the whole of the time. 



The first class includes those substances which completely destroyed the 

 locomotive power of the vibrios immediately, and completely prevented 

 their regaining it during the time the experiments were conducted : — 



Cresylic acid. 



The second class contains those compounds which nearly destroyed the 

 locomotive power of all the vibrios present when added, and afterwards 

 only one or two could be seen swimming about in each field : — 



Carbolic acid, sulphate of quinine, chloride of zinc, and sulphuric acid. 



The third class are those which acted injuriously on the vibrios on their 

 addition, leaving only a small number retaining the power of swimming, 

 but which allowed the vibrios gradually to increase in number, the fluid, 

 nevertheless, containing less life after sixteen days than the standard putrid 

 albumen-solution : — 



Picric acid and sulpho-carbolate of zinc. 



The fourth class includes those substances which acted injuriously at 

 first, but permitted the vibrios to regain their former locomotive power, 



