FACTS AND OBSER,VATIONS. 
741 
that water on being dropped Into it passes off in the state of 
vapour without assuming the spheroidal form, water be slowly 
dropped, each drop being allowed to evaporate before ano¬ 
ther passes in, and over the capsule a vessel be inverted by 
which the vapour ma}^ be condensed, it will be found on exa¬ 
mination to contain an appreciable quantity of nitrite of am¬ 
monia. The combustion of some substances also furnish the 
same salt, which M. Schoenbein refers not to the act of com¬ 
bustion itself, but to the concurrence of heat, water and air. 
In tills way he accounts for the presence of nitrite of ammo- 
Miia in rain-water; and as the evaporation of water is taking 
place at all times and in all places, so this salt should be 
found everywhere. By the same theoiy, he explains the for¬ 
mation of nitrites in the soil; the presence of nitrogenized 
matters there not being, he asserts, a sine qua non of nitri¬ 
fication, a proof of which is that the soil of Bengal contains 
them not. 
Digestion. —Mr. Briicke, of Vienna (CondaWs J. de 
Fliarmacie) has communicated to the Austrian Academy of 
Science an interesting paper on the influence of acids and 
pepsin in digestion, and on the question whether the latter 
is formed during that process; and also, in what manner the 
secretion of the digestive fluid takes jilace. By pepsin, 
Briicke understands the nondescript substance emanating 
from the glands of the stomach, and which, in an acid solu¬ 
tion, has the power of dissolving all albuminous matter within 
the stomach as well as without it. He found by a number 
of careful experiments that this power is strongest in a solu- 
.tion of gramme of dry hydrochloric acid in a litre of 
water, decreasing when the amount of acid rose above -}rd, 
or fell below -Tilths of a gramme. Contrary to the generally 
accepted views of Mulder, that part of the albuminous matter 
may pass into pepsin, Brlicke’s experiments go to show that 
such is not the case. He concludes that the stomach in an 
empty condition contains no acid fluid, which is only secreted 
by the action of the nervous system when food is introduced. 
Dr. Ebstein (ibid.) communicates a series of experiments on 
the action of saliva upon starch. Like Leuchs, Frerichs, 
and others, he found that starch, in contact with saliva, even 
in the presence of some acid, to a certain extent is converted 
into dextrin and sugar, and that the secretions of the 
stomach, though of an acid reaction, do not prevent this 
change. Dr. Ebstein remarks, that while secreting the 
saliva necessary for his experiments, he found it advisable 
to abstain from smoking, which, we suppose, he otherwise 
