Fbbbuaet 3, 1911] 



SCIENCE 



161 



and from the stomach or intestines they 

 are removed by the vomiting and purging 

 to which they themselves give rise.^ 



If a splinter lodges in one's finger and 

 is not removed, festering occurs and the 

 splinter is sloughed out. The throwing off 

 of a cold is merely the elimination by the 

 system of the disturbing factors and the 

 same may be said about the recovery from 

 any disease. Herter* says that ' ' disease is 

 generally the expression of a reaction on 

 the part of the cell to injurious influ- 

 ences." 



When studying chemical reactions, we 

 find some cases, such as the inversion of 

 sugar, in which the reaction products have 

 little or no effect on the reaction. In many 

 other cases, the reaction may come to an 

 end if the reaction products are not re- 

 moved. In these latter cases the reaction 

 products might be said to be toxic to the 

 system. Analogous eases occur in physi- 

 ology. Some secretions or reaction prod- 

 ucts are not toxic to the system, while 

 others are. Brunton' says that "cells ex- 

 crete poisons formed within their bodies 

 . . . [and that] an excessive quantity of 

 their own products is usually injurious to 

 cells. ' ' We all know that the waste prod- 

 ucts of digestion must be removed from the 

 intestines periodically or poisoning will 

 ensue, and we also know that the system 

 tends to react in such a way as to remove 

 these products. 



In the cases thus far considered, it has 

 been fairly clear what the response of the 

 system would be ; but this is not always so. 

 If a man goes out into the street and slaps 

 another man's face, he creates a state of 

 strain, which may be relieved by the other 

 man's running away. It is quite possible, 

 ' Brunton, St. Louis Congress of Arts and Sci- 

 ences, 6, 176, 1904. 



*" Chemical Pathology," 2, 1902. 

 " St. Louis Congress of Arts and Sciences, 6, 

 174, 1904. 



however, that the other man may knock the 

 first man down, or he may hand the first 

 man over to a policeman, if one happens 

 to be near. What happens depends on 

 the relative sizes and temperaments of the 

 two men and on the nearness of the police- 

 man. We can not make A, B and C repre- 

 sent the first man, the other man and the 

 policeman, and then interchange the let- 

 ters. We have the same thing in mixtures 

 of three liquids. If we add one liquid to 

 another, we always lower the vapor pres- 

 sure of the second to a certain extent. We 

 can not make any such definite statement 

 about what will happen if we add a third 

 liquid to the other two. The addition of 

 the third liquid may decrease the partial 

 pressures of both the other liquids or it 

 may decrease the partial pressure of either 

 one and increase that of the other. We 

 must know the specific properties of the 

 liquids before we can predict what will 

 happen. 



We know that an irritating substance is 

 often removed from the stomach by vomit- 

 ing; but if we administer poison continu- 

 ously for a long time, the system tends to 

 eliminate the irritating effect by becoming 

 immune to the poison. We need not hark 

 back to the mythical case of Mithridates, 

 who qualified for the throne by living on 

 all the known poisons while young. The 

 ease of the arsenic eaters is better authen- 

 ticated. '^ The whole of immuno-ehemistry 

 is an illiTstration of the applicability of our 

 law.' 



The most interesting field for the study 

 of our law is to be found in the natural 

 history sciences. Here we must consider 

 the survival of the race as well as the sur- 

 vival of the individual or we shall make 



" Brunton, St. Louis Congress of Arts and Sci- 

 ences, 6, 177, 1904. 



■ Cf. Le Dantec, " La Stabilitg de la Vie," 25, 

 1910. 



