Tissue in Autogenous and Homogenous Plasma. 459 



7 and 9. The results obtained in Experiment 9 are specially of interest, for 

 with plasma nine days old growth was obtained. This plasma coagulated well 

 but only gave 60 per cent, of positive results as compared with 100 per cent, 

 obtained with the same plasma when it was only five days old. This would 

 seem to show that the diminution of growth which occurred after the plasma 

 had been kept for a certain period was not entirely due to the lack of power 

 of coagulation, a lack which was considered the possible cause of failure in the 

 case of the testicular tissue. Further experiments were carried out to show 

 whether the increase of growth described above was due to the homogenity 

 of the plasma. 



Experiment 11. — Thyroid tissue was cultivated in fresh autogenous and 

 homogenous plasmata. Cultures were also made in plasmata eleven and 

 eight days old respectively. As usual no growth took place in the last two 

 groups. In the fresh autogenous plasma growth occurred in 60 per cent, of 

 the cultures, whilst in the fresh homogenous plasma it was present in 40 per 

 cent, and was rather less marked. 



The above results were confirmed by cross experiments carried out in the 

 same way as Experiment 5 was conducted in the case of the testicular tissue. 



Experiment 12. — Blood was removed from the lateral ear veins of two 

 rabbits, eight and three days before the experiment. Fresh blood was 

 removed at the time of the experiment and the thyroids were taken out from 

 the two animals at the same time. Cultures were made from each thyroid in 

 all six plasmata. In the eight-day plasmata all four groups showed no 

 growth. The thyroid tissue of animal A showed positive results in 100 per 

 cent, of the trials in the three-day-old autogenous plasma, but no growth at 

 all in the plasma of animal B. With the fresh plasma again there was slight 

 growth in 55 per cent, of the cultures in the autogenous plasma of animal A, 

 and no growth in that of animal B. In the case of the thyroid of animal B 

 there was good growth in 100 per cent, of the trials in the three-day-old 

 plasma of animal A, which in this case was homogenous, and no growth in 

 that of animal B. With the fresh plasma there was fair growth in the plasma 

 of animal A in 64 per cent, of the cultures and none in the plasma 

 of animal B. These results are shown in the table on p. 460. 



Thus this experiment confirmed what was found in the case of the testicle, 

 namely, that growth was not dependent upon any quality of the cells or upon 

 the fact that the plasma was homogenous or autogenous, but one plasma was 

 bad so that neither tissue would grow in it, whilst the other was good and 

 gave good results. 



