92 



Scientific Proceedings (hi). 



41 (1623) 



Preparation of collodion sacs for use in bacteriology. 



By Frederick L. Gates. 



[From the Laboratories of the Rockefeller Institute for Medical 

 Research, New York City'} 



A standardized method was described by which collodion sacs 

 suitable for intraperitoneal incubation and for other bacteriological 

 experiments may be produced in large numbers, sterilized, and 

 handled with convenience and the minimum danger of contami- 

 nation. 



Following the procedure of Prudden and McCrae, 1900, as 

 modified by Harris, 1902, the collodion sacs are made on a gelatin 

 capsule foundation which is then dissolved out with hot water. 

 The essentials of the method are the alcohol treatment of the 

 collodion membranes, as recommended by Brown, 191 5, and the 

 protection of the sacs in individual glass containers before and 

 after use. Various factors influencing permeability have been 

 subjected to experiment. 



Quantitative experiments on the dialysis of sodium chloride 

 indicate a uniformly high degree of permeability but the per- 

 meability conferred by the alcohol treatment is lost during heat 

 sterilization if the membrane was previously allowed to dry. 

 Simple tests with other substances show that the sacs are per- 

 meable to gases in solution, to inorganic salts, to dextrose, to 

 certain protein-split products which are nutritive to bacteria, and 

 to certain toxic products of bacterial metabolism, but they hold 

 back antibodies, unsplit proteins, and formed elements such as 

 bacteria and body cells. 



The preparation of the sacs is described in detail in the forth- 

 coming (January, 1 921) number of the Journal of Experimental 

 Medicine. 



