ON THE PLUM 



the growing of animal tissues in an artificial me- 

 dium, they discovered that such tissues might 

 retain their vitality and capacity for growth not 

 merely when cut from a living animal but when 

 they were taken from the tissues of an animal 

 recently killed. 



And if the body of an animal was placed in 

 cold storage from the moment of death, the tis- 

 sues were found to retain their vitality and ca- 

 pacity for growth for many days, instead of for 

 an hour or so only, as would have been the case 

 had they not been placed in cold storage. 



Moreover, the growing tissues themselves, 

 which under proper conditions could be kept 

 alive for weeks and even months, could be placed 

 in cold storage at a freezing temperature and kept 

 there for days without interfering with their sub- 

 sequent capacity for growth. Yet, if the slides 

 containing these same tissues were kept for half 

 an hour outside the incubator in a room at or- 

 dinary temperature, they would inevitably die. 



In Dr. Carrel's phrase freezing seemed to 

 "rest" the tissues and give them new powers of 

 growth. 



When we recall that vegetable protoplasm 

 and animal protoplasm are fundamentally of the 

 same constitution, built of the same elements and 

 subject in large part to the same rules of growth 



[21] 



