ACTIVE IMMUNIZATION FOR THERAPEUTIC PURPOSES 709 



Veer 1 the sensitization is not directly inherited, although the tendency 

 to spontaneous sensitization is inherited as a dominant character. 



Specific treatment with pollen extracts aims to desensitize the patient. 

 With pure pollens at hand skin tests may show the particular one to 

 which a patient is hypersensitive. A small abrasion is made and a 

 minute amount of the powdered pollen applied; the development of an 

 urticarial lesion within ten or fifteen minutes indicates that the person is 

 hypersusceptible to that particular pollen. Ophthalmic tests have also 

 been used for diagnosis and as a guide in treatment, but are not to be 

 recommended. 



The satisfactory preparation of hay-fever vaccine has not as yet been 

 accomplished, owing to the tendency of preparations to deteriorate 

 and loose in antigenic or desensitizing properties. Hitchens and Brown 2 

 prepare an extract of the pollen grains in physiologic salt solution, pre- 

 cipitate with acetone, and preserve the dried precipitate for the vaccine. 

 For use, the precipitate is dissolved in physiologic saline solution 

 sterilized by filtration and so diluted that the initial dose will contain 

 0.0025 mg. of protein. This vaccine maintained its therapeutic proper- 

 ties for two years. 



When the patient can be studied beforehand, a survey of his habitual 

 surroundings should be made. After noting all the flowering plants 

 which might reasonably come into question, skin tests should be made 

 with pollens of each of these plants in order to determine which of them 

 are responsible. In this connection it must be remembered that pollens 

 may travel great distances (Blackley) , and a field of grain several miles 

 away must be taken into account. A series of subcutaneous injections 

 with the proper pollen preparations should now be administered; in 

 my experience ten or more should be given with gradually increasing 

 doses at intervals of five or seven days, and the course of treatment 

 started in time to be finished a week or two before the expected attack. 



If the attack has already started, treatment should be begun at once 

 with a vaccine representing the pollens most likely to be responsible 

 for the attack. Not infrequently relief follows within twenty-four hours 

 after an injection. The injection must be given as frequently as indi- 

 cated to relieve the symptoms and make the patient fairly comfortable. 



The recent reports of Clowes, 3 Lovell, 4 Lowdermilk, 5 Ulrich, 6 Koess- 



1 Jour. Immunology, 1916, 1, 203. . 



2 Jour. Lab. and Clin. Med., 1916, 1, 457. (Excellent review of the literature.) 



3 Proc. Soc. Exper. BioL and Med., 1912-13, x, 69. 



4 Lancet, 1912, ii, 1716; Practitioner, 1914, xcii, 266. 



5 Jour. Amer. Med. Assoc., 1914, Ixiii, 141. 



6 Jour. Amer. Med. Assoc., 1914, Ixii, 1220. 



