72 Proceedings of Indiana Academy of Science 
cover has not perfectly solidified, bulging will occur. The sac is then 
immersed in water, where it is practically invisible. 
A properly made sac will not rupture if one were to blow into it 
with all one’s might. They are tested in this way before being used. 
By this method sacs for dialysing purposes, as described by the 
author” in a previous article, may be prepared with ease. 
The top of the sac is cut even, filled and immersed in distilled water 
in a cotton stoppered flask or tube. It is sterilized preferably in stream- 
ing steam or in the autoclave at 105 or 110° C. for 10 or 15 minutes. 
The sac is now ready to be inoculated with a suspension of organ- 
isms. A sterile pair of forceps is used to remove the sterile sac from 
the container in which it was sterilized. This sac is transferred to a 
sterile short tube or held in an upright position with sterile filter paper. 
The water is removed from it by means of a sterile Pasteur bulb 
pipette.“ With a similar pipette the suspension of organisms is intro- 
duced into the sac. The walls of the open end of the sac are dried 
with sterile filter paper and pressed together with a flat-surfaced sterile 
pair of forceps. Using a red-hot flattened iron wire or spatula, this 
surface is seared and then coated with several layers of collodion. 
The supposedly hermetically sealed sae is tested by taking hold of 
it with sterile filter paper and applying gentle pressure. If it is found 
found to be satisfactory it is placed upon sterile filter paper in a 
sterile dish and covered. 
The finished sae is now ready for insertion into the peritoneal 
cavity of a desired animal. For this purpose several animals are 
available. Guinea pigs, rabbits, rats, dogs, sheep and chickens are 
most frequently used. In this work the first three animals were em- 
ployed. 
In the case of the guinea pig and the rabbit, they may be held 
firmly upon their backs on an animal-board. If a suitable animal-board 
is not available they may be tied down in this position, as in the case 
with rats, by fastening cords to each leg and tying over a bridged 
board. 
The hair is removed from the abdomen with a pair of scissors, and 
after lathering well with soap and water the area is shaved. Alcohol 
and mercuric bichloride solution are used to disinfect this surface. 
After etherizing the animal a small incision along the median line 
is made through the skin of the upper part of the abdomen. The ab- 
dominal cavity is opened up next. With sterile pressure forceps the 
abdominal muscles are held up and the peritoneal cavity is exposed. 
The collodion sac is picked up with sterile forceps and introduced 
into the cavity and pushed well back under the aponeurosis. With a 
curved needle and silk thread the cavity is closed and the surface dis- 
infected. The skin is likewise sewed; also disinfected; dried with alco- 
hol followed with sterile filter paper and finally covered with collodion. 
The sac remains in the animal from forty-eight hours to several 
weeks and in some cases months. After the sac has remained in vivo 
12 Proceedings of the Indiana Academy of Science, pp. 265, 266—1916. 
13 Proceedings of the Indiana Academy of Science, pp. 266, 267—1916. 
