VIT.—InFivuence or Various THERAPEUTIC AND Toxic Sup. 
STANCES ON THE Proreotytic ACTION OF THE PANCREATIC FER- 
MENT. By R. H. Cuirrenpen anv Gro. W. Cummins, Pu.B. 
Wir the proteolytic ferment of the pancreatic juice, few sys- 
tematic experiments have been tried to ascertain the influence of 
those substances the frequency of whose use, as therapeutic or toxic 
agents, renders their action on this ferment a matter of no small con- 
sequence. The well known experiments of Heidenhain, Kiihne and 
Schmidt have been confined to the action of sodium carbonate, sodium 
chloride, and kindred salts of physiological importance. Pfeiffer* 
has indeed, in addition, experimented with a few of the sulphates of 
the alkalies and alkali-earths, but of the large number of metallic 
and other salts in common use, few have been tried, while the action 
of alkaloids and the gases occurring in the intestinal canal, has not 
been studied at all. 
Method employed. 
It is a characteristic of the proteolytic ferment of the pancreatic 
juice, that it exercises considerable digestive power in a neutral 
solution.t In view therefore of the fact that the ferment, while in the 
intestinal canal, may be obliged to act in an acid-reacting medium 
(due to acid-proteids) as frequently as in an alkaline or neutral one, 
it seemed advisable in the experiments, to employ a neutral solution 
of trypsin. Moreover, it becomes necessary to use such a solution, 
if salts of the heavy metals are to be experimented with, since in 
alkaline solutions, carbonates or oxides of the metals would be formed 
and thus affect the results; still, again, the action of all substances 
can be best studied in neutral solution, since under such conditions, 
no replacements or decompositions of any kind take place to compli- 
cate the action of the substance, other than the direct action on the 
ferment or the proteid matter. Hence, a neutral solution has in every 
case been employed as being the most satisfactory, while only such 
substances have been experimented with, as contained no free acid ~ 
or alkali, the destructive action of which is well known. 
* Centralbl. med. Wiss., 1885, p. 328. 
+ See Chittenden and Cummins, Amer. Chem. Jour., vol. vii, p. 46. Also Trans. 
Conn, Acad., vol. vii. 
