IMMUNITY 71 



exhibit great susceptibility to antiserum injection because 

 they are anaphy lactic to the horse serum, and while a few 

 deaths have occurred, they usually react by the appearance 

 of "serum sickness." This is a condition appearing five to 

 twelve days after serum injection, consisting of skin rashes, 

 malaise, fever, and albumin in the urine. The reaction 

 occurs most often in persons who have asthma when in the 

 presence of horses, and the physician should inform 

 himself as to this contingency. No reaction will appear 

 if the serum be given very slowly, or the first dose divided 

 by a few hours, or if a second injection be given in two 

 to four days. It is good practice to give always 0.5 c.c. 

 under the skin and follow with the remainder of the 

 desired quantity four or five hours later. If the reaction 

 from the smaller amount is very severe, the clinician must 

 debate the advisability of further injections. A single large, 

 rapid injection of horse serum should never be given to a 

 patient, because it might make him susceptible to horses 

 or to later serum injections, against which a second dose 

 within five days will protect him. Nurses should have a 

 hypodermic of T ^-Q gr. of atropin ready for emergencies, since 

 this drug is the only treatment for acute symptoms after 

 antitoxin injections. Akin to the above mentioned hyper- 

 sensibility of certain persons to the presence of horses are 

 the idiosyncrasies to pollen exhibiting itself as hay fever, and 

 to certain foods, shellfish and pork, which give intestinal and 

 cutaneous evidences of this susceptibility. There is at present 

 no adequate explanation nor satisfactory treatment of these 

 phenomena, those suffering from them simply being obliged 

 to avoid exposing themselves to the substances which intoxi- 

 cate them. 



The reader must not picture that these so-called anti- 

 bodies are substances that can be handled. They are invisible 

 chemical parts of the serum of the blood, and only perceptible 

 through extremely delicate laboratory procedures. The 

 present conception of their action was worked out by 



