Makgild. — Nature s Efforts at Sanitation. 151 



it will stand immense amounts of the poison. Then its blood 

 possesses the power of acting as an antidote to either the 

 germ itself or its poison. This has, as we all know, been most 

 successfully done, and we possess in this anti-toxin a most 

 powerful curative agent for this disease. This antidotal 

 power can easily be demonstrated. It is as apparent as the 

 neutralising power of acids and alkalis. Mix a certain 

 amount of the toxin with anti-toxin in a test-tube, inject the 

 mixture into a guinea-pig, and no effect will follow. If the 

 toxin alone were introduced the guinea-pig would very soon 

 die. So, too, in the living body we can show it, by injecting 

 two animals with the living germ of diphtheria and subse- 

 quently injecting into one of them a suitable dose of the 

 serum of the horse previously treated with toxin. In a day 

 or two the animal which received the germ alone will be dead; 

 the other, which also got the anti-toxin, will live. This has 

 been done so repeatedly for many years that there is now no 

 question about it. The same result always follows. Wherein 

 lies this anti-toxin power is a subject of much speculation. It 

 is as though the cells of the living body could be trained by 

 gradually exercising their normally existing powers to produce 

 an excess of the material which is antagonistic to the germs 

 and their products. This is the theory of a German scientist 

 named Ehrlich. The fact remains, however, that we can 

 educate the body of the animal artificially to increase its 

 resistance, and utilise the blood of this educated animal to 

 assist others in the fight against disease, herein following 

 Nature's lead, where she provides that any living body, if it 

 survive the first attack of a disease germ, possesses an in- 

 creased power of resistance against further incursions of that 

 germ. We merely exaggerate the process in one animal and 

 use the resulting products to aid others. 



It is possible that Nature too has a system of inoculation 

 without actually producing the disease. We know at least 

 that persons living in a country in which some disease is pre- 

 valent will acquire a certain degree of immunity without 

 actually suffering from that disease — at least, in any recog- 

 nisable degree. This is the case with malaria, yellow fever, 

 and typhoid. Persons coming newly to a country where 

 these diseases prevail are more liable to infection than those 

 born and brought up there. Perhaps there has been a series 

 of slight inoculations, as it were, with small or weakened 

 doses of the disease, not sufficient to produce more than a 

 passing indisposition, but sufficient to help in educating the 

 tissues. Be this as it may, we have Nature's own methods to 

 guide us and encourage us to further efforts in the direction of 

 artificially gaining immunity. The best proved example is in 

 vaccination against smallpox, where we use an allied disease 



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