ECONOMIC IMl'ORTANCE OF FUNGI 315 



of some animal that has had the given disease. As in the 

 case of the preparation of vaccine, the animal is first placed 

 in quarantine, under the most perfect sanitary surround- 

 ings; if found free from all contagious diseases, and other- 

 wise satisfactory, he is given increasingly large doses of 

 the toxin or the virus that causes the given malady. 

 This treatment may require as long as six weeks, and re- 

 sults in the formation of quantities of the antitoxin in 

 the blood. A quantity of blood is then drawn from the 

 animal, and the blood-serum isolated, filtered, carefully 

 tested for purity, content of antitoxin, and freedom from 

 disease-germs, and finally put up in glass syringe containers 

 ready for use. When a person is exposed to the given 

 disease {e.g., diphtheria), or has actually contracted it, 

 the serum is injected into his circulatory system, where the 

 antitoxin counteracts the toxin of the disease. The 

 patient is thus rendered passively^ immune. Serum- 

 therapy is now successfully employed in the treatment of 

 diphtheria, tetanus (lockjaw), hog cholera, and, with 

 more or less success, of infantile paralysis and certain 

 other diseases. 



Nothing corresponding to vaccination and serum therapy 

 is known for a certainty in the treatment of plant diseases. 



7. Antiseptic surgery. The greatest obstacle to suc- 

 cessful surgery has always been the presence of the rich 

 and varied microscopic flora, or plant life, in the air. 

 When a wound was opened or a cut made the germs com- 

 posing this flora found on the cut surface the most favor- 

 able conditions for their growth and multiplication, and 

 the poisons they secreted interfered with the healing of 



' Passively, because the antitoxin is not produced by the activity of his 

 own cells, as it is in the case of vaccination. 



