154 



ciiimilalcd. conhiiiKMl siilishmccs (';i|);il)lc of iiicrciisiii^f [he 

 rnlc ol' miilli|)lic;ili()n oT ril)r(jl)l;is(s. Similar c'Xj)criinenls wore 

 iiiulcrlnkcn witli injc'clioiis ol" slapliylococciis suspension, 

 d()<4 red blood corpuscles. Iur|)enline oi" bouillon into the 

 periloneuin ol" cliickens. 'I'he ifrowlli oT ribroi)las|s with ad- 

 dilioii ol' exlracls from lliese inl'lanied tissues, proved in 

 many experiments to be KM) pei- cent greatei- than that ob- 

 tained in l\ i n <i, e r solution. 



Recently (larrel and b^ 1) e 1 i n g ^*^! have proved that the 

 lymphocytes are capable of li'ansforming some of Uie serum 

 constituents into the more com])lex compounds necessary for 

 the nutrition ol" the fibroblasts and epithelial cells. 



Lym|)hocytes were cultivated on chicken |)lasma alone 

 in the D flasks; after a months cultivation. Iragments of 

 the plasma wei'e fixed, stained and I'xamined microscopic- 

 ally. It was ascertained that the lym])h()cyles were in full 

 acti\ity and had mulli])lied and invaded the entire culture 

 medium. 



In another intereslintf experiment of (lai'rel and l-', b c- 

 ling '^^) a fragment of spleen was placed at a shoi't distance 

 from a culture of fibroblasts; the rate of multiplication of 

 the fibroblasts was markedly increased, owing to the secre- 

 tion of growth-stimulating substances by the leucocytes. It 

 was fount! also that leucocytes do not live more than 10 daj'^s 

 in Tyrode solution. This denotes that in a non-nutrient 

 medium, they exhausted their residual energy from 7 — 10 

 days. Thus follows that, if leucocytes are cultivated in blood 

 serum for more than 10 days and are able to increase in 

 migration and multi|)licalion of fibroblasts, the material used 

 by them in the elaboration of the growth-i)romoling substan- 

 ces must come from the serum. 



The experiment was undertaken in this way. In a 1) flask, 

 a fragment of s])leen was ])lace(l 12 mm. from a fragment 

 of a pure culture of fibroblasts. The licfuid part of the cul- 

 ture medium was composed of pure serinn. therefore the 

 fibroblasts stopped their proliferation after 5 days. The leu- 



