260 
Proceedings of the Royal Society of Edinburgh. [Sess. 
hydrochloric acid was digested with a pepsin extract at 37°. A series of 
twelve digestions were made np for each antiseptic. At successive periods 
of half an hour each, one of these was withdrawn and saturated with 
sodium chloride. The progress of the reaction may he estimated by the 
decrease in precipitable material. In this case the necessary comparison 
was made by noting the time required to bring the members of the different 
series to the same state of clearness. The following table gives the 
number of half-hour periods which elapsed before the liquid reached its 
maximum clearness : — 
Chloroform, 1 per cent. . . . .10 
Formaldehyde, T .... 7 
Hydrocyanic acid, T „ .... 3 
Benzoic acid, T „ . . . .7 
Salicylic acid, T „ . . . .7 
In the case of chloroform, the digestion appeared to proceed rapidly in 
the earlier stages, but an opalescence remained which was not appreciably 
reduced on continued digestion. Whether this was due to the presence of 
edestin or not is impossible to say. 
General Conclusions. 
The results of the experiments show : — 
1. It is essential that the material should in all cases be as homogeneous 
as possible. 
2. None of the antiseptics examined can be indiscriminately employed, 
and it is necessary in every case to choose the antiseptic with due regard 
to the material as well as to the nature of the enzyme which is to be 
examined. 
3. It is not permissible to depend upon the efficiency of any one anti- 
septic in autolysis experiments, and the bacteriological examination is in 
all cases necessary. 
REFERENCES. 
(1) Proc. Roy. Soc. Edin ., vol. xxxi. p. 342. 
(2) Buchner, Ber ., 30, 31, 32; Zeitschr.f. Phys. Oh., 44; Bioch. Zeitsch ., 4. 
(3) Muntz, G.R., 80, 1250 (1875). 
(4) Salkowski, Deutsche mediz. Wochenschrift (1888), No. 168; Zeit. /. klin . 
Medizin (1890), Festschrift. 
