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3". that the effect of moderate quantities of atropin, which was 
variable at first and in my experiments was mostly inhibitory, may 
be altered in a constant, stimulating effect by repeated washing. 
Experiments with the small intestine of the guinea-pig. 
We now took the small intestine of the guinea-pig as the object 
of our investigation. 
Recently TRENDELENBURG*) has suggested an effective method to 
register graphically the peristaltic movements of the surviving small 
intestine of the guinea-pig and to determine to a certain extent in 
numerical values the action exercised on these movements by 
various poisons. 
TRENDELENBURG records that atropin (acting on the small intestine 
of the guinea-pig) is invariably inhibiting peristalsis. 
The great thing in our experimentation was to ascertain whether 
here also, as with the rabbit’s small intestine, its behaviour towards 
atropin is governed by its condition. We used TRENDELENBURG’s method 
and proceeded as follows: 
The guinea-pig was killed by a blow on the neck, the small in- 
testine was cautiously severed from the mesentery, and cleaned several 
times, with a warm fluid’) after Locke. Subsequently the intestine 
was cut into 5 parts, one of which was suspended immediately, the 
other pieces were put in separate dishes with Lockn’s solution, which 
was refreshed every now and then. 
The loop of intestine which was suspended in a vessel of 150 cc. 
capacity, was first left to itself with an interior pressure of 0 mm. 
H,O.; then the pressure was gradually heightened and we deter- 
mined at what pressure peristalsis first appeared (critical pressure). 
Then the interior pressure was lowered to O and after 3 minutes 
the critical pressure was again determined. 5 
This determination was repeated after 0,1, 1, and 5 mgr. of 
atropin had been added respectively. In accordance with TRENDELEN- 
BURG’S report, arrest of peristalsis took place, so that no peristalsis 
occurred any more even when the pressure was made considerably 
higher. 
After being carefully cleaned, a second loop was suspended, which 
was kept standing for some hours in Lockn’s solution; the same 
determinations were made prior to and posterior to the administra- 
tion of atropin. In most cases it appeared already now that the 
1) TRENDELENBURG, l.c. 
*) It is essential that the fluid should be prepared from pure salts and with 
pure water distilled from glass apparatus. 
