r.ill] iin Plti/^iirdl (V/r)nis(r// <i)i<l the l)octri,iir i>f riininniihj. 213 



pounds with albmiiiuous substances contained in these preparations, 

 which are more stable than the antigen or antibody itself, and which 

 are decomposed at higher dilutions. 



Some albuminous substances diminish the stability. Thus Madscn 

 and Walbuni found that an addition of Witte's peptone increases the 

 rate of decay of tetanolysin. 



As has already been said regarding tetanolysin, the rate of decom- 

 position increases very rapidly with temperature. This increase is 

 subject to the same law as is found for common chemical reactions, 

 namely, that an exponential formula is valid, i.e. the velocity of 

 I'eaction increases in a certain proportion for every degree. Thus 

 Madsen and Famulener found for a hemolysin from goat-serum : — 



Temperature, °C. . . . 51 51-5 52 52-5 53 



Velocity of decompositiou, obs. . 0-0139 0-025 0-038 0-060 0-095 

 calc. 0-0145 0-024 0-038 0-060 0-095 



This law is verified for a great number of substances in their 

 spontaneous decomposition as well as in their decomposition through 

 the presence of foreign substances, such as acids or bases, or in the 

 case of tetanolysin, of Witte's peptone. When foreign substances act 

 catalytically the influence of temperature generally is not so great 

 as in spontaneous decomposition, but nearly of the same order of 

 magnitude as in common catalytic processes — the velocity of reaction 

 increases in the proportion of about 1 : 2 or 1 : :-5 if the temperature 

 rises 10^ C. 



III.— Velocity of Reaction of Antigenes on other 

 Substances. 



Many of these reactions are of such a nature that only a certain 

 phase of the process may be accurately determined. Thus, for instance, 

 during the coagulation of milk by the aid of rennet, the moment 

 wlien the milk contained in a test-tube does not change its surface at 

 a slight inclination of the tube may be rather accurately determined. 

 After that the milk gets more and more viscous, but still no suitable 

 method of determining the times corresponding to these higher 

 degrees of viscosity has been found. Something similar is also true 

 regarding the agglutination. A certain degree of agglutination may 

 be determined with comparative accuracy, but not others. In similar 

 cases the time necessary to bring about just that degree of coagulation 

 or agglutination has been studied, when different quantities {q) of anti- 

 gene have been used. It has been invariably found that the greater 

 the quantity {q) the less the time {t), so that in most cases the product 

 {q. t) was constant. Madsen investigated for instance the digestion 

 of gelatin by means of pepsin by adding to a mixture of a solution 

 of 2 CO. of a 7 per cent, solution of gelatin and 1 c.cm. of * 4 per cent. 



