Decembeb 9, 1910] 



SCIENCE 



819 



resistance to one parasiticide is true of 

 other compounds of the same group, so 

 that a strain of trypanosome resistant to 

 trypanblue will also be resistant to trypan- 

 red — substances belonging to the same 

 group, although otherwise differing widely 

 chemically. It is a fortunate fact, how- 

 ever, that the parasite may still be success- 

 full}' attacked by compounds belonging to 

 other chemical groups. Probably the Ehr- 

 lich side-chain reaction best explains the 

 mode of action of the various remedies 

 used in the treatment of trypanosome dis- 

 eases. According to this theory, the try- 

 panosome, ILLvC a simple cell, contains 

 various atom groups, the so-called chemo- 

 receptors, which enter into a chemical re- 

 lationship with the germicide. In the case 

 of germicides belonging to the same class, 

 like trypanred and trypanblue, the same 

 atom group of the cell is attacked, while 

 other atom groups react with other classes 

 of antiparasitic agents, as for instance, 

 atoxyl, parafuchsin, etc. 



This theory also gives a clue in the treat- 

 ment of trypanosome diseases, since it 

 shows that instead of attacking simply one 

 atom group of the parasite with substances 

 with which it will enter into chemical re- 

 lationship it is better to attack simultane- 

 ously several atom groups. It is like 

 storming a fortress from various points 

 instead of attacking one point alone. 



As shown by Ehrlich, the effect of the 

 atoxyl treatment may be increased by the 

 simultaneous administration of trypanred, 

 trypanblue, or fuchsin, and by such com- 

 binations it may be possible to achieve the 

 essential aim, which is to rid the organism 

 of the parasites in the shortest possible 

 time. 



While these investigations were going 

 on, UHenhuth and Salmon published some 

 brilliant successes obtained with atoxyl in 

 the treatment of syphilis. Unfortunately, 



however, several cases of blindness were 

 reported from the use of this remedy. The 

 results achieved, however, were so promis- 

 ing that Ehrlich took up with renewed 

 vigor the fight against the spirochete of 

 syphilis with arsenical preparations. Soon 

 atoxyl was replaced by arsacetin, the 

 above-mentioned acetyl derivative of 

 atoxyl, with even greater success, but with- 

 out complete elimination of dangerous 

 after-effects. 



The constitution of atoxyl, elucidated 

 by Ehrlich, and that of arsacetin permitted 

 of a great variety of substitutions, and in- 

 numerable arsenic derivatives were syn- 

 thetized and tested as to their effectiveness 

 in the destruction of the spirochetes and as 

 to their degree of toxicity upon the animal 

 body, the object in view being that in the 

 doses required to kill the parasite they 

 must be free from any poisonous action 

 upon the patient. The culmination of this 

 long series of experiments is the wonderful 

 Ehrlich-Hata 606, which is chemically 

 p.p. dio.xy m.m. diamido arsenobenzol in 

 the form of the hydrochloride of its sodium 

 salt: 



-/ ^— A3=As— / N— ONa 



NaO— <^ 



NHj ■ HCl 



NHj • HCl 



A perusal of the publications appearing 

 in the medical press on the use of this 

 remedy is like reading tales from wonder- 

 land. With a remarkable unanimity it is 

 stated that in less than no time the mani- 

 festations of the disease disappear, and 

 that a condition of well being soon follows. 

 During the 14 months of medical investiga- 

 tion of the drug, about fifteen thousand 

 cases having been reported to Ehrlich, no 

 ill-effects traceable to its use when properly 

 administered have been observed. As re- 

 ported at a meeting in Frankfort a.M., at 

 which Ehrlich was present, two hundred 



