MESENCHYME CELLS OF TISSUE CULTURES 435 



It is not possible, from our knowledge, to form a definite 

 picture of the part played by the various visible structures in 

 the metabolism of the simplest cell. We know in a general way 

 that cells take in oxygen, water, salts, and food substances; 

 that these are built up into its own substance or transformed or 

 stored, and in the process carbon dioxide and other waste prod- 

 ucts* are formed which ultimately find their way to the exterior 

 of the cell. 



MATERIALS AND METHODS 



The experiments were made on cultures of mesenchyme cells 

 from various regions of chick embryos, six to nine days old. The 

 cultures were grown in either Locke's solution plus 0.5 per cent 

 dextrose, or in Locke-Lewis solution (the above solution plus 

 10 to 20 per cent of chicken bouillon). 



The potassium permanganate was dissolved either in normal 

 Locke's solution or in Locke's solution without the sodium bicar- 

 bonate. At first definite percentages of potassium perman- 

 ganate were used and the culture drop was usually entirely 

 washed away with the solution in strengths varying from 1 to 

 20,000 to 1 to 80,000. The rapidity of action depended on the 

 strength of the solution and how completely the old culture drop 

 had been replaced by the new. If, for example, a very small 

 drop of a 1 to 40,000 solution was added without washing away 

 the old drop, the new drop was so diluted that its action was 

 much retarded. 



Most of the cultures were stained with neutral red or with 

 neutral red and janus black no. 2 before the potassium perman- 

 ganate was added. One can follow the changes in the cell with 

 greater ease after the neutral red is deposited in the granules and 

 vacuoles and the janus black no. 2 in the mitochondria. Since 

 these structures in dead cells do not retain the dyes in the dilute 

 solutions as here used, we had a good criterion for cell death in 

 the loss of color. Dead cells do, however, take up these dyes 

 diffusely, if the solutions are strong enough. Some of the cul- 

 tures were fixed at varying periods after the application of the 

 potassium permanganate and stained in the usual manner with 

 iron haematoxylin. 



