PROBLEM 2. How We Can Cofiqiier Some Diseases 



numbers with the excretions. Once out 

 of the body they form spores in the soil. 

 Other horses, in grazing, swallow some 

 of the spores. Thus the germs, bv multi- 

 plying in one horse after another, be- 

 come plentiful in certain soils. 



When any soil, or an object that has 

 been in contact with the soil, gets into 

 a wound there is a chance that tetanus 

 spores will enter with it. When the 

 germs enter through a break in the skin 

 they become dangerous, especially if it is 

 a "puncture wound," one which is deep 

 and admits little air. Then the germs 

 multiply and form strong toxins which 



331 

 tain types of pneumonia, and various 

 other diseases doctors use immune serum 

 taken from some person or animal who 

 has had the disease. The serum is used as 

 a treatment. It is given after the person 

 has acquired the disease. You will easily 

 see that this treatment is different from 

 the active immunization described above. 

 Blood poisoning following operations. 

 Long before Pasteur's work on immuni- 

 zation was perfected and long before 

 physicians made a practice of immuniz- 

 ing against disease, equally important 

 work was being done along other lines 

 — the control of blood poisoning due to 



spread through the system, reach the bacterial infection which usually fol- 

 brain, and cause severe contraction of lowed operations. As always, when prog- 



the muscles (lockjaw). Fortunately, anti- 

 toxin against tetanus toxin is available. 

 As in diphtheria, if antitoxin is given 

 promptly, the toxin is neutralized and 

 kept from spreading. Antitoxin used 

 for treatment is supplied by horses and 

 is prepared in much the same way as 



ress is being made in science, there are 

 many investigators working on the same 

 problem. Toward the close of the last 

 century there were two scientists whose 

 names stand out particularly in connec- 

 tion with the study of blood poisoning 

 — the Hungarian doctor Ignaz Semmel- 



diphtheria antitoxin. See Exercise 7. In weis and Sir Joseph Lister (i 827-191 2), 

 all accidents and especially in those a Scotch surgeon. 



which involve deep wounds, it is wise to 

 have a prompt inoculation with tetanus 

 antitoxin. 



Recently, it has become possible to 



Up to about i860 physicians used hot 

 tar or red hot irons to prevent infection 

 after an amputation. They attempted 

 abdominal operations only when it was 



provide lasting immunity against tetanus unavoidable, for in such operations blood 

 by the use of a toxoid. After injection, poisoning almost always followed. 



the body builds up an active immunity 

 that lasts for several years. Physicians 

 now often give babies injections against 

 diphtheria and tetanus at the same time. 

 "Borrowing" antibodies. Diphtheria and 

 tetanus are the only common diseases 

 against which there are true antitoxins. 

 But we borrow other kinds of antibodies 

 against a good many kinds of diseases. 

 For treating measles, scarlet fever, cer- 



The discovery that germs could cause 

 disease led some physicians and surgeons 

 to suspect that the blood poisoning 

 which accompanied so many operations 

 might also be caused by bacteria. Lister 

 tried a strong disinfectant, carbolic acid, 

 a substance that he knew killed bacteria 

 in a culture. He dipped his hands and in- 

 struments in this before he went to the 

 operating table; he sprayed the body of 



