20 



oil excised corm-:! will he remembered, by which method 

 lu' ende;i\()iired lo soKc liie most rundameiihil |)rol)lems 

 of iiiri;iinm;ilion Mosl ol' Ihese expeiMinenls were .not Mctual 

 exphintatioiis. oi'teii the cells, which wen- to iiiidei'go an 

 examination wcri' in some way cojinected with the liody; 

 lor instance the many experimenls ol" inllammalion on Ihc 

 mesinterium. mem bran a iialatoria ol' ti'oifs, were 

 mostly done in connection with tlu' animal In olhei- cases 

 the animal was <veneraliy nsed as an incubator for the cells, 

 as. e. j^.. in the experiments on cliemf)laxis. wiien for 

 instance, while blood corpuscles were tempted to wander 

 into capillary tubes, placed in the abdominal cavity and 

 containinif attractive substances for the cells. In studying the 

 role played by Ihe connectiNC tissue cells under conditions 

 of infhunmation. Maxim off placed small ground glass 

 plates in the peritoneal cavity and afterwards examined 

 the invaded inflammatory tissue. 



It has been known that dead material lying in the orga- 

 nism, as for instance masses of fibi'in in the form of 

 thrombi in the blood vessels, can be organized and })rogres- 

 sively brought to disappear. What is going on is namely 

 that leucocytes and connective tissue cells migrate into the 

 fibrin and live there until the fibrin is liquified and resolved. 

 In other words, we here actually have a tissue culture in 

 vivo. Experiments resembling this process have been car- 

 ried out l)y Leo Loeb ^^-) in 181)7. He observed the cell- 

 wandering in blood coagulum and agar in vivo and clai- 

 med also to have done it in vitro, but the description of 

 the technique has not been published. 



Only when Harrison -^'^) in 1907 succeeded in studying 

 the i-egeneration of nerves from frog embryos in lymph out- 

 side the organism was this field of investigation opened. 

 Harrison's method of investigation was a logical out- 

 come of the embryological method of R o u x, I) r i e s c h 

 and Born, in which they tested the isolated embryonic 

 parts in regard to their function in the formation of or- 

 ganisms. 



