THE PROGRESS OF SCIENCE 



415 



larger, perhaps ethereal, existence and 

 of the conditions regulating intercourse 

 across the chasm. The speaker does 

 not repeat the evidence on which he 

 bases his faith, but it certainly has not 

 produced similar conviction on others 

 equally competent to judge. 



CHEMIOTHERAPY AND DB. PAUL 

 EHBLICH 



In his address before the recent Lon- 

 don International Medical Congress Dr. 

 Paul Ehrlich. director of the Royal In- 

 stitute for Experimental Therapy at 

 Frankfort-on-Main, reviewed the prob- 

 lems of chemiotherapy. He said that 

 the governing principle is that parasites 

 are only killed by those materials to 

 which they have a certain relationship, 

 which substances are "parasitotropic." 

 In the parasites and in the various 

 organs of the body there are specific 

 chemioreceptors which energetically at- 

 tract certain fixation groups ' ' some- 

 what as a magnet attracts iron. ' ' 

 It depends on the relationship between 

 the parasitotropism and the organo- 

 tropism whether a certain disinfectant 

 can be used as a remedy. The only 

 substances that can be considered thera- 

 peutic agents are those of which a frac- 

 tion of the tolerated dose is sufficient 

 to bring about therapeutic effects. 



This sounds rather obvious, and in 

 fact Dr. Ehrlich, like Mr. Edison, ap- 

 pears to have accomplished his remark- 

 able results by somewhat empirical 

 methods. This procedure he defends 

 in his address, saying at the outset 

 that the important factors in experi- 

 mental chemiotherapy are patience, 

 skill, luck and money, and in conclu- 

 sion : ' ' Considering the enormous num- 

 ber of chemical combinations which 

 must be taken into consideration in the 

 struggle with disease, it will always be 

 a caprice of chance or fortune or of 

 intuition that decides which investi- 

 gator gets into his hands the substances 

 which turn out to be the best for fight- 

 ing the disease. ' ' 



Whether by chance or by intuition, 



by luck or by genius, Dr. Ehrlich, with 

 the assistance of Dr. Hata and other 

 fellow-workers in his Frankfort labo- 

 ratory, in salvarsan, or "606," and 

 neosalvarsan, or "914," has discovered 

 drugs with remarkable therapeutic ef- 

 fects. Salvarsan is an arsenical com- 

 pound with the formula C 12 IE 12 ]N[,0 2 As ; .. 

 Its effects on the spiroehsetes of syph- 

 ilis are well known, it having already 

 been used in perhaps a million cases in 

 all parts of the world. Cures are some- 

 times effected by a single injection in 

 the first stages of the disease. It is not 

 so well known that even more striking 

 results have been attained with re- 

 lapsing fever, the fever immediately 

 subsiding after the injection of sal- 

 varsan, and the patients being cured 

 by one injection. The very rare cases 

 of recurrence are also readily curable. 

 Dr. Ehrlich states that it is possible by 

 one single injection of salvarsan to cure 

 framboesia (yaws), which is caused by 

 spiroehsetes and is a scourge of the 

 tropics, to cure it completely except in 

 rare cases where unimportant relapses 

 occur. Thus in Surinam a hospital in 

 which over three hundred patients with 

 framboesia were constantly under treat- 

 ment was closed and turned to other 

 uses after the introduction of the sal- 

 varsan treatment, as one single injec- 

 tion sufficed to cure the disease, and all 

 the patients but two could be dis- 

 charged. 



In the concluding paragraph of his 

 address Dr. Ehrlich said: 



The efforts of chemiotherapeutics 

 must be directed as far as possible to 

 fill up the gaps left in our defences, 

 more especially to bring healing to dis- 

 eases in which the natural powers of 

 the organism are insufficient. And I 

 believe that now definite and sure 

 foundations have been laid for the sci- 

 entific principles and the method of 

 chemiotherapeutics, the way is visible 

 before us — a way not always easy but 

 yet practicable. In the diseases due to 

 protozoa and spirilla extraordinarily 

 favorable results have already been 

 gained, as I have shown. There are 

 many valuable indications that in a 

 series of other diseases — small-pox, 

 scarlatina, typhus exanthematicus, per- 

 haps also yellow fever, and, above all,. 



