PKACTICE OF MEDICINE AND HYGIENE 



This method positively produces immunity, 

 and when diphtheria breaks out in a family of 

 children a very small injection absolutely pre- 

 vents the well from contracting the disease. 

 Its curative power is great in direct ratio to the 

 earliness of its employment. Now it is used in 

 all civilized countries. Already the num- 

 ber of lives saved by antitoxin in Europe and 

 America amounts to one hundred thousand 

 annually. It must be given early in the disease 

 because it cannot repair damage already done ; 

 it can only check the progress of the disease 

 from the time when it is given. It is important 

 that the antitoxin should be pure and of a 

 known potency. The amount of antitoxin in 

 serums is now required by law to be tested upon 

 animals before it can be sold. 



These discoveries have cost the lives of a 

 large number of guinea pigs and rabbits, and 

 are the result of years of patient study and ex- 

 periment. They are now subjecting a number 

 of horses to the inconvenience of receiving an 

 injection of micro-organisms into their blood 

 vessels and having some serum drawn off at 

 certain intervals. But these horses seem con- 

 tent, and look sleek and well, and take their 

 daily exercise with as much apparent relish as 



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