LIFE AND THE CELL 4 1 



"whence COMETH LIFE?" * 

 WILLIS R. HUNT 



Philosophers have for ages attempted to explain life and death and to 

 determine where one leaves off and the other begins. Present-day scientists 

 are continuing to investigate this burning question. 



Maybe the turning point is where the protein-building catalyst or 

 enzyme first appears. Although it is non-living itself, it no doubt is the 

 precursor of life, that is, it precedes and gives intimation of the coming 

 of life. Possibly the most primitive living unit may be the gene. Have any 

 of you ever seen a gene? No! It can not be seen even by the ultra micro- 

 scope, but if we are to account for the hereditary behavior of protoplasm 

 we must postulate invisible genes. Genes, as you remember, are the units 

 or atoms of heredity. Other assumptions are that the viruses or bacteri- 

 ophages may be the most elementary predator or form of life. 



It will not be possible to say just where or how life first appears, but some 

 evidence can now be given that the genes and the viruses are at the 

 boundary or border line of Hfe. 



Like life the origin of disease has been subject to many theories and 

 much speculation down through the ages. Primitive peoples believed that 

 evil spirits caused disease. In the Middle Ages invisible particles were 

 thought to be the cause. Bacteria were not even seen until the middle of 

 the seventeenth century, and were only proven to be the cause of disease 

 about sixty years ago. 



It has been estimated that there are seven hundred and forty-two living 

 agents causing disease in man. Thirty-one are ascribed to a something, called 

 a virus. There are some forty more viruses causing disease in the lower 

 animals, fowls, insects, fishes and plants. Examples of some virus diseases, 

 to mention a few, are smallpox, rabies, parrot fever, yellow fever, herpes, 

 mumps, measles, infantile paralysis, warts, epidemic influenza and the 

 common cold. Distemper of dogs, foulpox, cowpox, swinepox, jaundice 

 of silkworms and the so-called mosaic diseases of the tobacco, potato and 

 the tomato plants are examples of virus diseases in other groups of or- 

 ganisms. 



Just what the nature and properties of these "mysterious purveyors of 

 disease" are has been one of medicine's and bacteriology's greatest prob- 

 lems. Up to recently the following three questions had not been answered: 

 (i) Are viruses animate or inanimate? (2) Are they ultramicroscopic 

 entities related to bacteria? (3) Do they represent inanimate chemical prin- 

 ciples like catalysts or enzymes, for example, pepsin, an organic enzyme, 

 which stimulates digestive changes in the stomach? 



• Reprinted by permission of the Scientific Monthly, American Association for the 

 Advancement of Science. Copyright 1938. 



