1878. | Plaster of Paris as an Injecting Mass. 723 
or arseniate of soda is added, and the whole well mixed. Then 
8 cc. of carmine solution is stirred into the mass, and finally 
8 cc. of fifty per cent. acetic acid is poured in with constant 
stirring. The fine canula and rubber tube are filled with water to 
avoid getting air into the vessels. The syringe is then filled with 
the prepared plaster mass and the large canula of the syringe is 
connected to the fine canula by means of the rubber tube. The 
pressure should be steady and. continuous, There is very little 
danger of bursting arteries if the pressure is steady. 
Before the injection is commenced, a string should be put 
around the artery beyond the end of the canula and loosely 
knotted with a.surgeon’s knot. (In a surgeon’s knot the string 
is put through the loop twice as shown in Fig. III, 1.) As soon 
as no more mass can be forced into the vessels the surgeon’s 
knot should be tightened, and the fine canula and syringe 
thoroughly washed with water. All the dishes used in making 
the injection should be washed immediately before the plaster 
hardens. The most scrupulous cleanliness is necessary to pre- 
vent lumps of hardened plaster from clogging the syringe or the 
vessel which is being injected. 
In case veins are to be injected they should be, as far as possi- 
ble, emptied of blood, and the injection must be made from some 
peripheral vessel like the femoral or jugular veins, on account of 
the valves. It is well if the injection is made into the femoral 
‘vein, for example, to have the jugular open to allow the blood to 
flow out as the plaster is forced in. There is no danger of the 
plaster running out, for it cannot pass the valves. 
As a rule a dissection may be begun in half an hour after the 
injection. 
FORMUL FOR PLASTER MASSES. 
The amounts given are those necessary for an ordinary cat, and cost two to five 
cents: 
I, Finest plaster of Paris A92.Cc- 
Red lead or vermilion......... ene 5O grams, 
Either of the following restrainers OORS 
Ten tọ twenty per cent, aqueous solution of stcohol or glycerine, or a ten 
per cent. solution of arseniate of soda. 
a. Plaster. Too ce 
Restrainer 84 cc. 
appead geen of carmine 8 ce. 
ry carmine I gram, ammonia 2 cc. Grind the two in a mortar 
id, 22 cc. of twenty per cent. glycerine,) 
Fifty per cent. acetic acid : Sak 
VOL, XII.—NO,. XII 49 
