Tissue in Autogenous and Homogenous Plasma. 453 



In previous communications I have described fully the characters of 

 the growth of adult mammalian tissue in primary and in sub-cultures. 

 Having determined the nature of this growth, it became possible for me 

 to investigate the variation, if any, of the growth in autogenous and 

 homogenous plasma. The results of this investigation are detailed in this 

 paper. 



The tissues of adult rabbits were used and the technique of Carrel was 

 carefully adhered to. Four hundred and thirty-three cultures were made, 

 the testicle, thyroid, and kidney being the tissues mainly used. A few 

 experiments were made with tissues of the spleen but owing to the 

 amount of emigration of cells, apart from true growth, which occurs with 

 this tissue it was found difficult to make accurate comparative experiments. 

 These experiments were therefore discontinued. 



The details of the experiments on the testicular tissue and the results will 

 be fully described. The other tissues will be considered more briefly as the 

 experiments on them were carried out on the same lines. 



Testicle. 



One hundred and twenty-two cultures were made with testicular tissue. 

 It was found that the plasma of the rabbit kept in ice would not continue 

 fluid for longer than about an hour. After this time it coagulated and 

 became useless. To overcome this difficulty the plasma was placed in a 

 sterile tube which was corked and sealed with paraffin, and the tube was 

 immediately placed in a mixture of salt and ice contained in a thermos flask. 

 By changing the mixture of salt and ice every two or three days the plasma 

 could be kept frozen hard for an indefinite time. When required for use 

 it was removed from the mixture and at room temperature soon became fluid. 



Experiment 1. — Plasma was removed from Eabbit A six days previous to 

 the cultural experiment and kept frozen. At the time of the cultural 

 experiment blood was collected from the carotid artery of Eabbit B and the 

 plasma separated. Cultures of testicle of Babbit B were made in the usual 

 way in both plasmata. Twelve cultures were made in the homogenous 

 plasma and twelve in the autogenous. Of those in the homogenous, good 

 growth occurred in all, whilst of those in the autogenous plasma only eight 

 grew and growth was less extensive in these. 



Experiment 2. — Cultures of testicle were made in homogenous plasma 

 which had been kept frozen for three days and in fresh autogenous plasma. 

 In both the same testicular tissue was planted and the cultures were made 

 at the same time and under identical conditions. The cultures in homogenous 

 plasma again gave 100 per cent, of positive results whilst those in autogenous 



