COLLODIUM SACS. 
(By S, B. Grubbs, Passed Assistant Surgeon, and Edward Francis, Assistant Surgeon, 
United States Marine-Hospital Service.) 
Since the publication of the work of Metchnikoff, Roux, and 
Salimbeni* on the toxins of cholera, the growing of cultures in 
collodium sacs placed in the peritoneal cavities of animals has 
become a common procedure not only at the Pasteur Institute, but 
in all bacteriological laboratories when it is desired that the cul- 
ture in its growth shall be raised in Aurulence through the action 
of the nutrient body fluids and yet be protected from the influence 
of the body cells and phagocytes. 
As usually made, the sac is molded over the end of a glass rod 
by dipping it several times into the collodium solution, after which 
it is peeled off (Pasteur Institute). 
Rovy“ slips inside the sac a glass tube which is perforated and 
constricted, and he fixes the free border of the sac to the glass tube 
at a point just below the constriction by means of heat, pressure, 
a silk ligature, and additional collodium. 
McCrae,* following Prudden, employs a glass tube, to the heated 
end of which he attaches a gelatin capsule which acts as a. tempo- 
rary frame over which the collodium is molded. The capsule is 
then removed by dissolving it in hot water. 
In the techniques just referred to there are several delicate 
manipulations which greatly hazard the chalices of getting a per- 
fect sac ; 
1. There is the danger of tearing and destroying the sac in ]>eel- 
ing it oft' the rod. 
2. There is considerable difficulty in attaching the sac si^curoly 
to the glass frame ; and, 
3. If no frame is used, the sac has no siqiport, may become 
shriveled, and is liable to tear on removal from the animars abdom- 
inal cavity if bound around by adhesions. 
’Toxhie et antitoxiiie cholerique Aim. de I’lnstitiit Pasteur 180G, X. 
■' Laboratory work in bacterioloj^y. 
^Journal of Experimental Medicine, vol. 5. 
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