Jai,T 1, 1904.] 



SCIENCE. 



U 



miliar with the production of poisonous 

 matters by other vegetable cells, and the 

 development of ptomaines, or cadaver poi- 

 sons, was sufficiently well understood to 

 suggest at once the formation of analogous 

 substances in the living organism. ■ Hence 

 the doctrine of the toxins as the important 

 chemical factors in the causation of certain 

 diseases, when once clearly stated, made 

 rapid headway and is now very generally 

 admitted and recognized. The investiga- 

 tion of bacterial intoxications has become 

 a chemical problem of rare fascination and 

 importance, and through this work entirely 

 new departments of research have been 

 opened up, bringing into the practise of 

 medicine, as well as into the literature, new 

 ideas and new methods. The development 

 of the notion of toxins was followed by that 

 of the antitoxins, the potent agents which 

 check or prevent the harmful work of the 

 toxic ferments. The theory of the action 

 of these substances on each other is largely 

 a chemical one and is founded on a basis 

 of experiment. It appears that in many 

 cases studied toxin and antitoxin combine 

 in fairly definite and constant proportions, 

 which would necessarily be the case if their 

 union is in any sense a chemical one. The 

 behavior of one with the other has been 

 compared to that of an acid with a base, 

 but it is more like the combination of active 

 salts to form complex double salts of en- 

 tirely distinct properties. The extreme 

 toxicity of potassium cyanide, for example, 

 is modified by combination with iron com- 

 pounds to produce the salt of a new and 

 far less potent acid. 



Few topics in medicine to-day attract 

 the attention given to natural and acquired 

 immunity. The history of scientific in- 

 vestigation in this field is not old, but 

 already its literature has become enormous. 

 Immunity may exist with reference to bac- 

 teria, or to the toxins produced by bacteria, 

 and in either ease it may be inherent or 



natural or it may be imparted. The 

 natural immunity of many animals to bac- 

 terial invasion does not necessarily involve 

 any direct chemical action, and in the most 

 widely accepted notion yet advanced to 

 account for this kind of immunity certain 

 large ceUs of the body, which have been 

 called phagocytes, or devouring cells, play 

 an important part. These seem to seize 

 upon the foreign iavader and destroy it by 

 a kind of digestive process. Such a prop- 

 erty is observed in the large Avhite cor- 

 puscles or leucocytes of the blood, and it is 

 likely that a chemical action is indirectly 

 concerned here. The cells may produce 

 some specific chemical substance which is 

 a poison for the attacking bacteria. It has 

 also been held that in the gradual and 

 spontaneous disintegration of these cells 

 substances are thrown into the serum 

 which have the real germicidal action. 

 These are the alexins of Buehner, and in 

 the theory of the latter they are enzyme- 

 like substances. What the exact facts are 

 we do not know, but I refer to the point to 

 emphasize the growing tendency to look for 

 the chemical factor in every body phe- 

 nomenon. 



In the study of acquired or developed im- 

 munity to bacterial toxins we find the most 

 ambitious introduction of purely chemical 

 theories. In this field the labors of 

 Pfeiffer, Buehner, Bordet, Ehrlieh and 

 others are preeminent, and in all cases the 

 chemical idea appears as an essential fac- 

 tor. This is peculiarly true of the so-called 

 'side chain theory' of Ehrlieh, which at the 

 present time attracts the widest attention. 

 Years ago Pasteur introduced the notion of 

 molecular asymmetry into chemical science 

 and pointed out in effect the importance 

 of the conception of configuration in deal- 

 ing with certain problems. In 1894 dur- 

 ing the progress of his famous investiga- 

 tions on the bodies of the sugar group, 

 Emil Fischer published some remarkable 



