Biology and Medicine 445 



(in round numbers) men inducted into all branches of the 

 army that year 71,955 men or five and a half per cent were 

 found to have venereal disease of some sort, most of which 

 was brought with them on their entrance into camp. After 

 enlistment the rate materially decreased, due to the vigorous 

 methods adopted by the army, both for repressing vice about 

 the army camps, and for educating the men and otherwise 

 guarding them against this evil. Perhaps the worst fea- 

 ture of syphilis from the standpoint of its prevention is the 

 difficulty of recognizing it in its latent form. Its trans- 

 missibility from husband to wife and vice versa and from 

 parent to child is well known. But the disease is curable 

 and marriage of a former syphilitic is permissible when such 

 cure is definitely established. The difficulty is to determine 

 when such cure has been established. An individual with 

 no apparent symptoms of the disease may yet be infected 

 and capable of infecting consort and children. Here too has 

 lain the chief medical difficulty in the control of prostitution. 

 Another very serious feature of the disease is the difficulty 

 of recognizing it in its incipient stages. The earliest symptom 

 of the disease is the chancre or sore, which appears usually 

 about three weeks after exposure, and then often cannot be 

 diagnosed with certainty. If treated immediately upon its 

 appearance it disappears, a positive diagnosis cannot be made, 

 and treatment will probably be relaxed or abandoned alto- 

 gether, leaving the disease latent in the body, to break out 

 anew at some future time. On the other hand, if treatment 

 is delayed until a positive diagnosis is established valuable 

 time is lost, and the disease may obtain so firm a hold upon 

 the system that its eradication becomes extremely difficult if 

 not impossible. Biology has largely solved these difficulties 

 by providing means of diagnosis, even in the absence of all 

 external symptoms. 



If a small amount of sheep's blood be injected into the 

 body of a rabbit there develops in the blood of the latter the 

 power to break down the red corpuscles of the sheep, liberat- 

 ing the coloring matter or haemoglobin which they contain. In 

 this rabbit's blood are two chemical substances, one of which 

 destroys the sheep 's .corpuscles in the presence of the second 

 substance, the three forming a chain (according to modern 

 bacteriological theory) a-b-c, a being the sheep's corpuscles, 

 b, the go-between substance or ' ' amboceptor, " and c, the 

 destructive substance, or " complement. " The latter is prob- 

 ably present normally in the blood of any higher animal, 

 it is the former or "amboceptor" which is formed by the 

 injection of the sheep's blood into the rabbit. This rabbit's 

 blood is now heated to 133 F. in order to destroy its "com- 



