140 



The rcsiill \\;is lli;il llic l\ni|)h(K'ylt's were miicli more scn- 

 silixc to llu tissue Juice lli;in the Tihroljlasls. 'Plie optimum 

 condition \v;is lound to he ni)oul .'{() per eenl tissue juice. 



These ()l)ser\;itioiis are of <j;i"eal importance and may 

 pr()l)ahly partly settle the (pu'stion ol' the origin of lihro- 

 hlasts from larjfe mononucleai" lym|)li()cytes during' inllam- 

 mat()r\- conditions, as has heeii discusst'd trom tlu' days ol' 

 \' i r c h o w and (lohnhoim. 



The action of homoloffous serum on the growth ol lym- 

 phocytes was also studied and it was found that the cells 

 were very sensilixc to the inhibiting influence of the serum. 



Tliis method of oht linini* ])ure cultures of larjfe mono- 

 nuclear leucocytes is a ])liysiol()gical elective, because all 

 other types of white blood corpuscles disap|)ear spontane- 

 ously wben cultivated under the said experimental conditions. 

 First the polymorphonucleai* lencocytes disappear and a few- 

 weeks later also tlie small mononncleai' cells. It was [)Ossiblc 

 to retain tlie lai\^e mononuclear leucocytes in tlie cultui'cs 

 for neaidy three months. The rale of multiplication was 

 much slower tban that of fil)rol)lasts and epithelimn. An 

 interesting fact is tliat the cultures of these cells were mucli 

 more sensitive to all influences, wlielher of physical or che- 

 mical nalnre. And still the most interesting and important 

 resnll from lliese investigations is the transformation of 

 the large mononnclear leucocytes into tissue-forming cells 

 of the ly|)e of fibroblasts. Xol only it is interesting to observe 

 the perfect morphological change these cells may undergo, 

 but more im|)ortant, it seems to me. is the change which 

 can take place to tissue-forndng cells from a type of cell 

 which under ceiiain conditions al)S()lutely does not show- 

 any tendency to form anastomosis. Maxim off "" has 

 l)robai)ly ol)ser\-ed the beginning of the same transformation. 



Vov a long time it lias been assumed that the lymphocytes 

 are the origin of the various types of connective tissue. 

 Kenaut and Dubreuil "■' wei'e of th;d opinion ^ni] the 

 observations of .M a x i m o f f i'"). (lai'i-el and 1-] he ling 



