78 Chittenden and Painter—Influence of Therapeutic 
In accord with our results, Detmer* has found that the presence 
of carbonic acid invariably increases the amylolytic action of the 
diastase of malt. The same fact was previously observed by Bas- 
witz.t O. Nasse,{ however, has stated that the activity of ptyaline 
in human mixed saliva is not materially affected by oxygen, hydro- 
gen or air. With carbonic acid, however, he noticed acceleration in 
amylolytic action. 
Nature of the action of the metallic and other salts. 
In what manner do the metallic and other salts act when they, by 
their presence, retard or completely stop the amylolytic action of 
saliva? Is it a process of gradual or sudden destruction of the fer- 
ment, or does the metallic salt combine with the ferment, forming a 
compound incapable of ferment action? or again, is the ferment 
mechanically thrown down with the precipitate of albumin or globu- 
lin produced by the addition of the metallic salt to saliva, or lastly 
does the salt by its mere presence introduce a condition unfavorable 
to the action of the ferment? All of these questions are interesting 
ones, and possibly all of them might be answered in the affirmative 
and be correct for some one or more of the substances experimented 
with. . 
It is obvious that the presence of 10 or 20 per cent. of such a salt 
as sodium chloride or potassium nitrate in a digestive mixture might 
retard the action of the ferment, since solutions so saturated, even 
with the products of digestion, do not admit of vigorous ferment 
action. But the larger number of metallic salts decidedly retard 
amylolytic action when present to the extent of only a few thou- 
sandths of one per cent., consequently their action must be of an 
entirely different nature. A number of these salts, such as mercuric 
chloride, are well known precipitants of albumin, but the saliva being 
so greatly diluted, in great part for this very reason, cannot yield 
sufficient precipitate with the mercury salt to mechanically precipi- 
tate the ferment. As a matter of fact, when the mercuric chloride 
solution is added to the diluted saliva, a very faint turbidity only, 
is produced. If now, some of the small percentages of mercuric 
chloride are added to the starch solution and then larger quantities 
of saliva, thus giving a larger amount of ferment together with a 
larger amount of accompanying albumin and globulin, what would 
* Zeitschrift fir physiol. Chemie, vol. vii, p. 3. 
+ Berichte d. deutsch. chem. Gesell., vol. xi, p. 1443, 
f Pfliiger’s Archiv, vol, xv, p. 471-481, 
