XXVI 



MAN'S FIGHT FOR SURVIVAL 



Preview. What is health? • What is the biological significance of 

 death ? • Causes of disease : Unfavorable environmental factors • Degenera- 

 tive diseases • Man and his parasitic worms : Parasites acquired through 

 improperly prepared foods; parasites acquired directly by man; parasites 

 acquired indirectly by man; malaria as an economic problem; yellow 

 fever and its relation to insect vectors ; typhus ; other diseases carried by 

 insects; animals other than insects may spread disease; the relation of 

 bacteria to disease ; certain bacteria, called pathogens, cause disease ; how 

 do bacteria enter the body? some important bacterial diseases • What is 

 immunity? The mechanism of immunity; active acquired immunity; 

 some examples of diseases where active immunity is practiced ; bacterins 

 and their use ; the menace of the carrier ; vaccines and attenuated organ- 

 isms; hay fever; passive acquired immunity • Are parasitic diseases con- 

 querable? • Suggested readings. 



PREVIEW 



The growth of knowledge of man's relation to parasites and the 

 prevention of disease has been a matter of evolution. Primitive man 

 used charms and incantations to ward off disease. During Roman 

 times traditional methods were handed down from the- Greek and 

 Roman philosophers. The first glimpse of real knowledge came in 

 the seventeenth century with such discoveries as that of the circula- 

 tion of blood by Harvey, the relatively modern diagnostic work of the 

 physician, Sydenham, and the surgical skill of John Hunter. In 

 the eighteenth century progress was marked by the work of Jenner in 

 relation to vaccination for smallpox. In the nineteenth century a 

 rapid advance began with Pasteur's discovery of bacteria as one of 

 the causes of disease, the isolation of some of man's most deadly 

 enemies by Robert Koch and others, and the foundation of modern 

 antiseptic surgery by Lister. During the latter part of this period 

 many discoveries of ways and means of disease prevention were 

 made, such as the beginnings of water filtration, the pasteurization 

 of milk, and more emphasis on the control and prevention of various 

 diseases. The twentieth century marks a notable departure into the 

 field of public health and a rapid development of public health work. 



608 



