MITOCHONDRIA IN TISSUE CULTURES 341 



It is during- the first two or three days then that w(^ may 

 compare the cells and their structures with those found in the 

 embryo. The mitochondria have been studied during this early 

 period when their appearance and behavior can be considered 

 normal. The close resemblance of the mitochondria found dur- 

 ing this early period to those found in the chick by other ob- 

 servers (Benda, Aleves, Duesberg, Dubrueil, Cowdry, etc.) shows 

 that they at least are not noticeably altered in the culture. We 

 are justified, we believe in assuming that our findings concern- 

 ing mitochondria apply as well to the normal cells within the 

 embryo as they do to the cells of the tissue culture. 



TECHNIC 



The ordinary technic for the cultivation of tissues in Locke's 

 solution as described b}^ Lewis and Lewis ('11, '12) was used. 

 We found great variations in the amount, duration and character 

 of growth in different solutions. This was apparently not due 

 to the slight variation that occurs in the weighing out of the 

 salts or sugar, which enter into the composition of the solution, 

 since these can be varied considerably and good growth obtained. 

 The trouble lies either in the distilled water, a contaminated 

 container for the solution, poor chick material, or some manip- 

 ulation during the process of explantation, which we vary un- 

 knowingly. In repeating this work one should make several 

 trials until a solution favorable for growth is obtained. When a 

 favorable solution is once obtained it can be kept for months, 

 provided the dextrose is not added to the stock solution. 



Chick embryos were taken out of the egg under aseptic condi- 

 tions and put into 10 or 20 cc. of sterile Locke's solution (NaC'l 

 0.9 per cent, CaClo 0.025 per cent, KC\ 0.042 per cent, NaHC^Og 

 0.02 per cent, dextrose 0.25 per cent at 39°C. A piece a few milh- 

 meters in diameter of the desired tissue was then cut out and 

 placed in another dish which contained 10 or 20 cc. of sterile 

 Locke's solution at 39°C. This small piece was then cut up 

 into numerous very small pieces. These were drawn up into 



