THE SCHICK TEST FOR NATURAL DIPHTHERIA ANTITOXIN 231 



that the injection is intracutaneous and not subcutaneous (Fig. 68) . When 

 0.1 c.c. is injected the patient should experience a slight stinging sen- 

 sation and a white anemic and raised spot, resembling a wheal, appears 

 (Fig. 69). If this spot is not seen the injection has probably been subcu- 

 taneous and is unsatisfactory. 



After twenty-four hours a positive reaction is shown by an area of 

 redness and induration. The experienced observer may detect a reaction 

 by simply running the finger over the area of injection, when the in- 

 duration is easily felt. Persons reacting negatively show nothing more 

 than the point of puncture, and at times a very small area of redness 

 measuring f inch or less in diameter (Fig. 70) . 



When time permits it is better practice not to read the reaction until 

 forty-eight hours have elapsed, as a few persons will show a false reaction 

 of redness and slight edema at the end of twenty-four hours which dis- 

 appears after forty-eight hours, whereas the true toxin reaction remains 

 or may slightly enlarge within forty-eight hours, to be followed by 

 gradual disappearance of all signs and brownish discoloration and slight 

 desquamation of the epithelium, lasting several weeks. 



In a special study with Dr. Moshage 1 of these pseudoreactions I 

 have found that they are to be largely ascribed to a peculiar hypersensi- 

 tiveness of the skin in certain individuals, as well as to a protein reaction 

 due to the soluble protein constituents of bacilli and beef in the toxin as 

 described by Park, Serota, and Zingher. For this reason it is advisable 

 to use highly potent toxins requiring high dilution, and to reduce trauma 

 as much as possible by injecting not more than 0.1 c.c. as the dose. 



The safety and practical value of the diphtheria toxin reaction has 

 been established since announced by Schick by numerous investigators 

 in this country, as Park, Zingher and Serota, 2 Kolmer and Moshage, 3 

 Weaver and Maher, 4 Graef and Ginsberg, 5 Moody, 6 Bundesen, Moffett 7 

 and Conrad, 8 Linenthal and Rubin, 9 as well as by several European 

 investigators. 



In the presence of an outbreak of diphtheria, therefore, the physician 

 should take cultures and apply the toxin test to all persons exposed. 

 At the end of twenty-four hours he has the evidence offered by both at 



1 Jour. Amer. Med. Assoc., 1915, 65, 144. 2 Arch. Pediat., 1914, xxxi, 481. 



3 Amer. Jour. Dis., Child., March, 1915, 189. 



4 Jour. Infect. Dis., 1915, xvi, 342. 



6 Jour. Amer. Med. Assoc., 1915, 64, 1205. 



6 Jour. Amer. Med. Assoc., 1915, 64, 1206. 



7 Jour. Amer. Med. Assoc., 1915, 64, 1203. 



8 Jour. Amer. Med. Assoc., 1915, 65, 1010. 



9 Boston Med. and Surg. Jour., 1915, clxxiii, No. 12. 



