6l READINGS IN BIOLOGICAL SCIENCE 



iron. More than half of the bulk of protoplasm consists of water, while 

 salts including sodium, potassium, calcium, magnesium, iron and man- 

 ganese, are also present in small quantities. 



Constant activity is one of the most important characteristics of proto- 

 plasm, as it is in all life. Protoplasm has an energy content which inspires 

 constant interaction between it and the outside environment. Like the 

 engine of your automobile, protoplasm absorbs fuel in the form of food 

 and then burns it to provide the energy necessary for its varied activities. 

 The biologist has named this process metabolism. Protoplasm has as its 

 distinguishing characteristics the powers of growth, reproduction and a 

 keen sensitiveness to environment. The living cells, therefore, feed, breathe, 

 grow and reproduce. During these activities, the carbohydrates, fats and 

 proteins in the cell, through oxidation and other processes, undergo 

 changes by virtue of which their chemical structure is transformed, en- 

 ergy meanwhile being absorbed from them to the cell. To keep the life 

 process going, it is necessary that a new supply of carbohydrates, fats and 

 proteins be continually fed into the living cells and that the waste prod- 

 ucts produced by the various processes be carried away. 



The modern discovery that all life is based on a stuff called protoplasm 

 is one of the greatest in the history of science, and it has led to an eager 

 school of scientists who are striving toward the creation of life in the 

 laboratory. Consequently, scientists have achieved some stirring results 

 which hold the promise that we may be on the threshold of exciting events. 



After a person is dead, many parts of the body, it has been proved, 

 remain alive for hours or days. Hair and nails, for example, grow longer 

 after death because the cells from which they grow are still living. In 

 Russia, Dr. S. J. Tchenchulin apparently kept the severed head of a dog 

 alive for more than three hours, while his colleague. Dr. A. Kubliako, 

 kept a human heart functioning for at least thirty hours outside the body 

 that once had owned it. 



Professor Woodruff of Yale has further demonstrated that there need 

 be no termination to the continued existence of pure-lived protozoa, or 

 uni-cellular animals. He found no natural death in a culture of Farainecmm 

 in 8,500 generations equal to 250,000 years of human Hfe, and the culture 

 was going as well at the end as at the beginning. Morgan of Columbia found 

 that ^5oth part of a worm will regenerate and be "younger" than the 

 original. These tests pointed to the sensational conclusion that life cells 

 and tissues are potentially immortal, a conclusion which now seems to have 

 received definite confirmation at the hands of Dr. Alexis Carrel, world 

 famous surgeon of the Rockefeller Institute. 



Twenty years ago. Dr. Carrel set out to determine just what life power 

 was inherent in the tiny myriad cells known to make up our bodies. He 

 posed several questions and set out to find answers for them: When man 

 or any other animal died, did he die completely in all parts of the body, or 



