100 



Scientific Proceedings (74). 



the blood or closely related forms. In pneumonia induced in 

 animals heavily stained with lithium carmine, no cells stained with 

 carmine took part in the formation of the exudate. No plasma 

 cells were seen. 



56 (1120) 



Technique of cultivating human tissues in vitro. 

 By R. A. Lambert, M.D. 



[From the Pathological Laboratory of the Presbyterian Hospital.] 



Several difficulties have been encountered in the cultivation of 

 human tissue in vitro. 



In the first place human fibrin is readily liquefied by fresh 

 tissue, so that when human plasma is used as a culture medium 

 the cells find no framework on which to grow. Losee and Ebeling 

 overcame this difficulty by transferring the tissue fragments at 

 frequent intervals before liquefaction took place. We have solved 

 the problem in another way which does not necessitate frequent 

 transfers. The method consists in using as a culture medium 

 chick plasma, the fibrin of which resists digestion, with the ad- 

 dition of an equal quantity or more of human serum. In this 

 medium the cells grow much more actively than in pure chick 

 plasma. Since there is no liquefaction it is not necessary to make 

 subcultures oftener than every 5 to 7 days. 



That fresh human tissue cannot always be obtained when 

 wanted has appeared to be another difficulty in the study of human 

 tissues in cultures. We have found, however, that human tissues, 

 just as those of lower animals, may be preserved for 5 to 10 days 

 before using, if cut into small pieces, covered with salt solution 

 and put aside in a cool place. Serum and Ringer's solution possess 

 no advantage over ordinary salt solution and a temperature of 

 1 5° C. appears to be as satisfactory as a lower temperature. 

 Tissues obtained at autopsy may be used though often infected. 

 We have obtained good growth of connective tissue from pieces 

 of liver and testis taken from a body six hours after death. 



The sterilization of infected tissues constitutes a problem 

 which we have not yet solved satisfactorily. Skin, which is 



