56 ; REPORT-—1874. 
branes, at once excites it. The application of dilute hydrochloric acid and 
induced electrical shocks have a similar effect. Sulphate of magnesia and 
other purgatives, however, instead of exciting secretion at once, do so only 
after an interval; and for some time it was supposed that they did not excite 
secretion at all. The experiments of Moreau, in which he injected magnesium 
sulphate into a loop of intestine and left it there for four hours, showed that 
the failure of previous experiments was due to their having applied it to 
the intestine for too short a time. These experiments were repeated by 
Vulpian, and also by Brunton, with similar results. 
Your Committee, starting from the facts we have briefly enumerated, 
endeavoured to ascertain, first, whether other neutral salts have a similar 
effect to magnesium sulphate on intestinal secretion; secondly, whether any 
other compounds have the power of preventing such action ; and thirdly, what 
are the nerves which regulate this secretion during life. 
Serres I. Action of other neutral. salts on intestinal secretion. The 
method adopted in each case was as follows :— 
A cat was chloroformed and an opening was made through the abdominal 
wall in the middle line. A coil of small intestine was then drawn out 
through the opening, and four ligatures were tied round it at a distance of 
10 centimetres (4 inches) from each other, so as to isolate three pieces of 
intestine from each other and from the remainder of the intestinal tube. 
The measured quantity of solution was then injected into the middle loop, 
either by a very fine Wood’s syringe, when the fluid was quite clear, or 
by making a puncture in the middle loop close to one end, inserting the 
nozzle of a syringe, and then after the injection of the fluid tying another 
ligature round the intestine close to the wound so as to prevent the exit of 
any fluid. This proceeding hardly diminished the length of the loop by 
more than 3 millimetres (3 of an inch). 
The intestine was then returned to the abdominal cavity, the wound sewn 
up, and the animal allowed to recover. After about four hours it was killed 
by a blow on the head with a hammer; the abdominal cavity was opened and 
the intestine examined. 
Experiments were made with potassium acetate, chlorate, ferrocyanide, 
iodide, sulphate, neutral tartrate, with sodium acetate, bicarbonate, chloride, 
phosphate, and sulphate, as well as with tartrate of potash and soda. [For 
particulars see Series I. and Table I. in Appendix. } 
From these it appears that several of the other neutral salts possess a 
similar action to that of magnesium sulphate, though none are so constant or 
so marked in their action. 
The amount of secretion obtained from similar pieces of intestine with 
similar quantities of the salts differed considerably in different experiments. 
The cause of this we have not yet determined. It is not improbable that it 
depends to some extent on the stage of digestion when the injection was 
made; but this we purpose to ascertain hereafter. ; 
Serres II. We next tested the effect of various drugs in preventing this 
action of neutral salts, and for this purpose took a saturated solution of 
magnesium sulphate as that of which the action is the most constant yet 
ascertained. 
In some cases we mixed the modifying agent with the magnesium sulphate 
in order to obtain the local action of the drug on the mucous membrane, in 
others it was introduced into the circulation by subcutaneous injection so as 
to obtain its general action on the nervous system. The drugs tested in the 
former way were :— 
