HYPERSUSCEPTIBILITY IN MAN 233 



was transfused with the blood of a donor who was a victim of horse 

 asthma. The recipient, two weeks later, while driving in a carriage, 

 was seized with a typical asthmatic attack and subsequently showed a 

 positive skin reaction to horse dandruff. This apparently is a case of 

 passive transfer of a natural hypersusceptibility. No data have been 

 collected to show whether such a variety of passive sensitization is per- 

 manent in man or exhibits the same evanescent character as occurs in 

 animals. Passive sensitization of animals has been produced by Koess- 

 ler, but Cooke, Flood and Coca, as well as Ulrich, have been unable 

 to confirm this. Our own experience with one case of human hyper- 

 susceptibility to rabbit serum failed to demonstrate passive transfer 

 into guinea-pigs. 



Tests for Hypersusceptibility. The manifestations of hyper- 

 susceptibility may be general or lo'cal, depending on the mode of in- 

 oculation and the amount of material employed. If the dose can be 

 carefully regulated, the hypersusceptible state may be demonstrated by 

 inducing a general reaction, as in the tuberculin reaction. Owing to the 

 fact that individuals may be extremely sensitive to certain proteins, as 

 in the case reported by Boughton (see page 230), the use of the general 

 reactions for diagnostic purposes is limited to those in which severe 

 general reactions are not likely to appear. The local reactions give 

 equally satisfactory information in man and are devoid of serious 

 results. These local reactions are based fundamentally upon the studies 

 of Arthus, published in 1903. He found that if animals are given 

 several subcutaneous injections of normal horse serum at three- or 

 four-day intervals, the first three injections are absorbed readily, but 

 the fourth is followed by a local inflammatory reaction and subsequent 

 injections are likely to be followed by more severe inflammation, necrosis 

 and gangrene. Animals rendered sensitive by these first two or three 

 injections could be killed by intravenous or intraperitoneal injections. 

 The Arthus phenomenon was early employed as a means of detecting 

 hypersusceptibility resulting from bacterial invasion, but it has now 

 found widespread employment in the detection not only of the presence 

 of changes incident to infectious disease but also for the determination 

 of sensitiveness to a large number of proteins of animal and vegetable 

 origin. Although hypersusceptibility may exhibit itself in respiratory 

 phenomena as in hay fever, horse asthma, etc., or in gastro-intestinal 

 disturbance, as in sensitiveness to egg-white, definite local reactions 

 may be evoked by the introduction of the proteins into or under the 

 skki and these local reactions may be accompanied by general symp- 

 toms, such as fever, headache, malaise and transitory leucopenia fol- 

 lowed by slight leucocytosis with an associated esinophilia. 



Toxins in Hay Fever. The studies of Dunbar assumed that the irri- 

 tant agent in pollens is a toxin. He based this conclusion on the fact that 

 he could prepare a so-called antitoxic serum " pollantin " by immunizing 

 anjrnals and subsequently claimed that he could demonstrate antibodies 

 by precipitin and complement-fixation tests. Clowes found positive 

 precipitation and complement fixation in some but not all cases before 



