HYPERSUSCEPTIBILITY IN MAN 231 



are instances of hypersusceptibility. The sensitive state appears to be 

 inherent in the cells of certain individuals, and although not directly 

 inherited, Cooke and Van der Veer have found that the tendency to 

 spontaneous sensitization appears to be heritable, that it follows the 

 law of Mendel and appears as a dominant character. Nevertheless, 

 there is a possibility that sensitization may be acquired in some manner. 

 Cooke, Flood and Coca maintain that artificial sensitization cannot be 

 produced by pollens. Heyl, however, has obtained from the pollen of 

 ragweed an albumin, a proteose and a globulin and found that mixtures 

 of the albumin and proteose possess definite sensitizing properties upon 

 animal inoculation. Individuals who have been given horse serum 

 therapeutically become somewhat sensitive to subsequent injections of 

 horse serum, but only in rare instances is the sensitiveness shown as a 

 coryza or asthma when near horses. The chance of sensitization by in- 

 jection of other proteins is not great. The possibility of sensitization 

 by virtue of the material gaining access to the body through the respira- 

 tory or intestinal surfaces is apparently remote. There is little satis- 

 factory evidence that protein materials in the form of dust gain access 

 to the circulation through the respiratory membrane. Ulrich, however, 

 reports the experimental sensitization of guinea-pigs by nasal insuffla- 

 tion of pollens and of horse serum, but reports that rabbits cannot be 

 so sensitized. It is impossible, under these circumstances, to exclude 

 the possibility that the material is ultimately swallowed, and sensitiza- 

 tion effected through the intestinal tract. The ingestion of proteins as 

 foods ordinarily leads to such changes in the protein in the process of 

 digestion that the absorption of the products cannot produce sensitiza- 

 tion. On the other hand, it is known that if given in large amounts and 

 given under certain circumstances native protein may gain access to 

 the blood stream through the intestinal tract. Rosenau and Anderson 

 maintained that sensitization could be effected by feeding horse serum 

 to guinea-pigs, but the failure of Besredka, as well as of other investi- 

 gators, to confirm this leaves the matter in some doubt. As against the 

 acquisition of hypersusceptibility in hay fever, Dunbar and also Cooke, 

 Flood and Coca have found that patients may be sensitive to the pollens 

 of plants indigenous to foreign countries and with which the patients 

 have never come in contact. 



Hay fever, rose fever and similar disturbances are due to the pol- 

 lens of certain plants and the flowering period of these plants deter- 

 mines the seasonal prevalence of the disease. The pollens responsible are 

 those which are disseminated by winds ; those plants which are pollin- 

 ated by insects do not produce hay fever. Scheppegrill points out 

 also that the direct effects of pollens are. of importance as they may 

 be locally irritant to both normal and hypersusceptible individuals, 

 either because of the mechanical effect of spiculated pollens or because 

 of the discharge from the pollen of irritant juices. Local reactions may 

 be increased by anatomical malformations in the nose and pharynx, such 

 as deviation of the septum, polyps, adenoids, and the condition may 

 entirely subside following correction of these abnormalities. Strouse 



