THE PHENOMENA OF INFECTION 471 



following the use of diphtheria antitoxin and other thera- 

 peutic sera are fortunately so rare that they should not be 

 considered too seriously when indications for the use of 

 such sera arise. However, there are certain precautions 

 which can and should be employed, and which may aid 

 materially in avoiding the untoward effects following the 

 administration of these remedies. Much has been accom- 

 plished by the efforts of various pharmaceutical houses to 

 prepare an antitoxin from which a large proportion of the 

 foreign albumin contained in horse serum has been removed, 

 and such products should be used exclusively whenever 

 possible. It would, furthermore, appear to be well to make 

 a preliminary test with regard to the sensitiveness of any 

 given individual to the serum employed. This may be 

 done by the injection of a very small test dose (0.05 c.c.) of the 

 serum and watching for rapid evidences of toxic action in 

 the patient. Alarming signs, if they occur, develop usually 

 within an hour after treatment; and if no sign of poisoning 

 occurs within this time, it may be safely assumed that the 

 individual does not contain within his body the special 

 ferment required to split up the material injected, and a 

 second injection may be made with impunity, provided 

 the interval of time elapsing between each is not sufficiently 

 long to admit of the development of sensitization. In a 

 disease such as diphtheria this is, of course, a matter which 

 does not enter into consideration in the treatment of any 

 given attack. The preliminary injection of atropine has 

 been advised by Auer, who found that 18 out of 25 sensi- 

 tized guinea-pigs which had been given atropine sulphate 

 recovered from the second injection, while of 24 untreated 

 controls, only 6 survived. 



When symptoms of sensitization appear immediately or 

 soon after the injection, the use of ether by inhalation is 

 to be recommended, as Besredka found that in experi- 

 mental sensitization animals narcotized with ether did not 

 succumb to the second injection. When it is ascertained 

 that a given individual is sensitive, and nevertheless the 

 use of therapeutic sera is imperative, it may be given by 



