224 THE PRINCIPLES OF IMMUNOLOGY 



blood three or four dynes, from which reduction the animal gradually 

 recovers. Upon investigation of the electrical potential of sera it was 

 found that a current of eight volts shows a precipitate at both electrodes 

 in the case of normal serum, but that with a so-called anaphylactic serum 

 the precipitate collects almost entirely in the negative pole. Although 

 Besredka's former idea that the injected serum contains a separate 

 sensibilisinogen which leads to the formation of sensibilisin in the cells, 

 and an antisensibilisin which combines with sensibilisin upon the second 

 injection of the serum is not in accord with prevailing ideas, yet he was 

 one of the first to propose a physical theory. Thus he stated in a gen- 

 eral way the majority of the facts seem to indicate that the phenom- 

 ena of anaphylaxis and anti-anaphylaxis are reduced to the action of 

 precipitation and adsorption which upset the mutual relations of the 

 colloids. Besredka no longer insists upon the separation of the two 

 elements of protein, but is of the opinion that the important site of 

 reaction is in the nerve cells. He believes that the second injection 

 of the protein meets with the preformed sensibilisin in the cells and 

 produces there either a liberation or absorption of energy, thermal or 

 otherwise, and that this reaction leads to the phenomena of anaphylactic 

 shock. He compares the reaction to the mixing of water and sulphuric 

 acid. If the water is added suddenly to the acid there is an explosive 

 liberation of the heat of hydration. If the water is added slowly, the 

 heat is generated more gradually and no serious manifestations take 

 place. So with anaphylaxis, if the injection is in a single large dose, 

 anaphylactic shock is produced, but if several small doses are given, 

 there is a series of very slight shocks leading to no serious disturbance 

 and so desensitizing the body that serious results cannot follow a 

 subsequent large injection. Besredka argues that the inhibitory effect 

 of anesthetics supports his contention that the nerve cells are of great 

 importance in production of anaphylactic shock, but the work of numer- 

 ous investigators shows that the broncho-constriction and fall in blood- 

 pressure occur in spite of anesthesia, and that the reaction may be fatal 

 if the intoxicating dose be sufficiently large. Bronfenbrenner points 

 out that anesthetics increase the antitryptic power of the blood 100 

 per cent, or more, thus inhibiting the liberation of proteases and the 

 consequent production of toxic split products. As a further objection 

 to Besredka's conception is the fact that the experiments with isolated 

 organs and perfusion demonstrate that smooth muscle reacts and that 

 the phenomenon is by no means confined to the nerve cells. When 

 calorimetric and metabolism experiments can be performed with nerve 

 tissues, definite information can be obtained in regard to energy changes 

 in these tissues in anaphylaxis. 



Anaphylactoid Phenomena. In the discussion of the theories of 

 anaphylaxis references have been made to anaphylatoxin and certain 

 similar substances. As has been pointed out, these substances may be 

 protein in character, may represent certain decomposition products of 

 protein, or may be non-protein colloids. It is even maintained that 

 arsphenamine is to be included in this category of colloids. The in- 



