78 THE RELATION OF BACTERIA TO DISEASE 



appearance of "serum sickness." This is a condition 

 appearing five to twelve days after serum injection, con- 

 sisting 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. 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 i-o gr. of atropin ready for emergencies, since this 

 drug is the only treatment for acute symptoms after 

 antitoxin injections. 



The jeader must not picture that these so-called 

 antibodies are substances that can be handled. They 

 are invisible chemical parts of the serum of the blood, 

 and only perceptible through extremely delicate labora- 

 tory procedures. The present conception of their 

 action was worked out by Dr. Ehrlich, a German 

 chemist and physicist. His theory, broadly speaking, 

 assumes a group of substances circulating in the blood 

 which can be stimulated to meet and destroy invaders, 

 and thereby protect the body. Besides the three 

 methods above outlined, in which practical therapeutic 

 use has been made of the known facts in the study 

 of immunity, still others have been devised, but they 

 are scarcely yet out of their experimental stage. 



