148 PHYTOTOXINS A^D ZOOTOXINS 



The processes involved in hay fever would seem to be characteristically in the 

 nature of an anaphylactic reaction to a foreign protein, in which case we cannot 

 speak of either a toxin or an antitoxic seriun. Prausnitz suggests that the serum 

 of immunized animals contains so large a supply of antibodies that the minute 

 quantities of foreign protein are digested beyond the toxic-fraction stage almost 

 immediately, and hence no reaction is observed. This explanation would agree 

 with the experimental inhibition of the toxicity of pollen mixed witli antiserum, 

 and at the same time with the clinical inefficiency of the serum. The hyper- 

 sensitization seems to be established spontaneously through inheritance, but no 

 antibodies can be demonstrated in the blood of sensitized persons, altliougli the 

 cells of the skin and mucous membranes are reactive.io 



(The effects of the phytotoxins on the blood are discussed under 

 "Hemolysis" in Chapter viii. Vegetable hemolytic poisons that do 

 not resemble the toxins, e. g., giucosides, etc., will also be found dis- 

 cussed under the same heading.) 



ZOOTOXINS 18 



SNAKE VENOMS 19 

 This important class of poisons, first thoroughly investigated by 

 AVeir Mitchell (1860), and :\Iitchell and Reichert (1883), has re- 

 cently aroused great interest through its relations to bacterial toxins 

 and the problems of immunity. The poisons of different species of 

 snakes seem to have much in common with one another, whether de- 

 rived from the Elaperine snakes (cobras and numerous other Indian 

 and Australian snakes), or Viperidce (including most poisonous Amer- 

 ican snakes), or Hydrophime (the poisonous sea-snakes), although 

 very characteristic differences exist between each. 



The essential anatomical differences between the different classes of snakes are 

 as follows: Colubrid<c, which include all the non-poisonous snakes, have no 

 mechanism for injecting poisons into their victims. Cohihrid<i' renenosce are 

 venomous snakes resemi)ling in many particulars the harmless Colubrines, but 

 having short poison fangs, firmly fastened to the maxilla in an erect position; 

 in this class are included the cobra and the venomous snakes of Australia. 

 Viperidce, or vipers, are characterized by a highly specialized apparatus for in- 

 jecting the poison; their poison fangs are very long, and the miixillary bone, to 

 which they are fastened, is so articulated that it rotates about a (|u;n-ter of a 

 circle when the snake strikes, bringing the fangs into an erect position. Tlie 

 fangs are canalized and pointed at the end like a hypodermic needle, and the 

 poison is forced through them under considerable pressure by a large muscle that 

 contracts over the salivary gland. Accessory fangs in various stages of develop- 

 ment are also present to replace any fang lost in action. All the poisonous 

 snakes of North America, with one insignificant exception, belong to the vipers, 

 and to a special class known as the "pit vipers," because of the presence of a 

 deep pit of unknown function above the maxilla. The exception mentioned is 

 the "coral snake" found on the coast of Florida, around the Gulf of :Mexico and 



10 See Cooke, Flood and Coca, Jour. Immunol., 1917 (2), 217. 



18 Full review and literature given by Faust, "Die tierischen Gifte," Braun- 

 schweig, 1906; also in Abdorhalden's Ilandbuch, Vol. II. Sachs, Kolle and Was- 

 sermann's Handbuch, 1913 (2), 1407. 



19 Elaborate review and bibliography given by Noguchi, Carnegie Institution 

 Publications, 1900, No. Ill: also bv Calmette, "Lea v<^nins. les animaux veriimaux 

 et la s^-rotherapie anlivenijueusc." Paris. IMasson, 1907: Calmette, Kolle ami Was- 

 sermann's Handbuch, Vol. IT, j). 1.S81; witli reference 1o Xortli American snakes, 

 see Prentiss Willson, Arch. Int. :\red., 1908 (1), 516. 



