122 



Scientific Proceedings (58). 



Effect of Gentian Violet on Growing Adult Tissue. 



For this purpose transplants of pericardium from the adult 

 frog were used; and the media employed was frog's plasma, 

 obtained after the usual technique (Harrison, 1910). The effect 

 of the gentian violet was studied by adding it to the plasma into 

 which the transplants were made. In the first experiments the 

 plasma contained gentian violet in a dilution of 1 to 2,000. Defi- 

 nite growth of tissue occurred in this dilution; but there seemed to 

 be some retardation of growth, and in all subsequent experiments a 

 weaker dilution of the dye was used (1 to 20,000). Here growth 

 was active, keeping pace with the controls. Indeed, in some series 

 the growth in stained media definitely outstripped the controls, 

 and the possibility of a stimulation of tissue growth by weak 

 solutions of the dye should be borne in mind. This growth oc- 

 curred in spite of the fact that the tissue plant when placed in 

 plasma containing dye became intensely stained. 



Our impression after careful study of these growing transplants 

 is that the cell nucleus itself is stained and that this nuclear 

 staining is intra -vital and does not interfere with growth. This 

 much is certain, that in those transplants resting in stained plasma 

 the cell nuclei stand out with great clearness, a clearness by no 

 means to be observed in the controls, and that these clearly seen 

 nuclei appear violet. It is also certain that the cell outline, even 

 when weak dilutions of the stain were used, was rendered very 

 distinct; and in the experiments made with stronger dilutions 

 the protoplasm was definitely stained. 



In these observations we paid particular attention to the 

 endothelial cells which grew out in definite sheets. Many of the 

 specimens gave us the impression that the dye might be exercising 

 a selective action ; for when the tissue was grown in stained media 

 the new growth took the form of a definite sheet of endothelial 

 cells, not observed when the tissue was grown in unstained plasma. 

 Further experiments are now under way to determine what is the 

 explanation of this undoubted fact. 



We have been able to follow the cell division of these stained 

 cells and to observe the whole process of cell division, though the 

 karyokinetic figures have not been clearly seen. We have also 

 observed actively moving cilia in newly produced ciliated endo- 



