Tissue in Autogenous and Homogenous Plasma. 455 





Animal A. 



Animal B. 





Homog., 3 days old. 

 Good, 100 per cent. 



Autog., fresh. 

 . Slight, 75 per cent. 



Homog., 6 days old. 

 Medium, 70 per cent. 

 Homog., 3 days old. 

 Good, 100 per cent. 



Autog., fresh. 

 Fair, 60 per cent. 









Experiment 4. — Plasmata were removed from two other animals and kept 

 frozen, one eleven and the other eight days before the cultural experiment. 

 Just before this experiment was commenced blood was removed from the 

 lateral ear vein of another animal and the plasma separated. Cultures were 

 then made under identical conditions in the four plasmata, viz. : homogenous 

 eleven days old, homogenous eight days old, homogenous fresh, and autogenous 

 fresh. In the first two groups every piece of tissue died and there was no 

 evidence of growth. The tissues in fresh plasma grew in the usual way and 

 to an equal extent. The growth in the autogenous plasma was perhaps a little 

 more extensive than that in the homogenous plasma (Plate 20, figs. 5 and 6). 



These experiments showed that testicle grew better in homogenous plasma 

 that had been kept frozen for three days, but not at all in plasma that had 

 been frozen for more than six to eight days. The question as to whether 

 growth was better in autogenous or homogenous plasma was still undecided, 

 The following experiment was therefore devised to settle this point. 



Experiment 5. — Two rabbits were taken. Blood was removed by puncture 

 from the lateral ear vein of each, ten and three days before the cultural 

 experiment, the plasma being separated and frozen. At the time of the 

 experiment blood was removed from the carotid artery of each and the testicle 

 taken out. Thus there were obtained from each animal three plasmata, one 

 which had been frozen for ten days, one for three days, and one fresh, that is 

 six in all. The testicle of each animal was cultivated in all the plasmata, 

 making twelve separate groups. The cultures were fixed at the end of 

 48 hours and stained so that the early growth-characters might be seen, 

 these being considered more capable of comparison than the later stages when 

 the growth was well advanced. 



In the case of the testicle taken from animal A there was no trace of 

 growth in the ten-day-old plasma, whether taken from animal A or 

 animal B. With the three-day-old plasma that from animal A, autogenous, 

 showed well marked growth, but that from animal B, homogenous, showed 

 very slight growth and marked vacuolation of the plasma. With the 

 fresh plasma there was a fair amount of growth in both series, but whereas 



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