THE CUTANEOUS REACTION IN LEPROSY. PRELIMINARY 



REPORT.' 



By Oscar Teague. 

 (From the Biological Laboratory, Bureau of Science, Manila, P. I.) 



One of the greatest advances made in the study of immunity during tlie 

 past two years has been the recognition and investigation of a condition 

 which is in a sense the opposite of immunity, namely a condition of hyper- 

 sensitiveness. It has been Imown for a long time that when an animal is 

 injected with certain toxic substances, it may react and produce antibodies 

 which render it more resistant to the toxin in question; but it is only 

 recently that marked attention has been given the fact that under certain 

 circumstances an animal may react and become more suspectible to the 

 substance injected. The hypersentitivenes of the guinea pig to injections 

 of horse serum has been carefully studied and will illustrate the point in 

 question A normal guinea pig may be given 5 or 6 cubic centimeters of 

 horse serum subcutaneosly or intraperitoneally without showing any ab- 

 normal symptoms. But if a guinea pig be given one-tenth of a cubic 

 centimeter of horse serum and, after a period of ten days or more has 

 elapsed, 5 cubic centimeters of horse serum are administered intraperito- 

 neally, the animal, after a few minutes, shows signs of restlessness, then 

 falls over on its side, struggles convulsively and dies of respiratory failure. 

 The first injection of a minute quantity of horse serum has "sensitized" 

 the guinea pig so that horse senim is now extremely toxic for it. If the 

 second injection had been given within the ten-day interval, the guinea pig 

 would not have been affected. This incubation period of the hypersen- 

 sitive reaction has lead some investigators to believe that the process 

 depends upon the formation of antibodies here just as in the case of the 

 immunity reactions. The hypersensitiveness when once established has 

 been shown to last a year and even longer, and probably is present as 

 long as the animal lives. 



Instead of horse serum, probably almost any other foreign protein could 

 be used to call forth hypersensitiveness, and this has been already demon- 

 strated for egg white, proteins from certain plants, bacterial extracts and 

 other substances. 



The study of the immunity reactions brought forth abundant fruit 

 for the practical side of medicine in the discovery of diphtheria and 



" Eead before the Manila Medical Society on September 8, 1908. 



32.3 



