HISTORIC DEVELOPMENT OF IMMUNOLOGY 61 



after one hour, the individual may be said not 

 to be hypersusceptible. If, after such a test, 

 the individual shows no reaction, or a reaction in 

 which the symptoms consist of mild pruritus, 

 sneezing, difficult respiration, etc., the physician 

 may feel absolutely sure that the injection of the 

 entire dose of serum at the end of an hour will 

 produce no ill effects. 



Precautions The risk of serum injection is 

 much less than that attending the administra- 

 tion of many drugs, and should never weigh in 

 the treatment of diphtheria or even in prophy- 

 lactic injections when exposure to the disease 

 is at all likely. It may, however, have some 

 bearing on the indiscriminate immunization of 

 normal individuals. In patients with a history 

 of asthma or with suspected status lymphati- 

 cus, it may be advisable to give a very small 

 test dose and to precede the therapeutic dose 

 with the administration of 0.01 grain of atro- 

 pin hypodermically. 



