Decembeb 31, 1920] 



SCIENCE 



629 



or otherwise modify tlie infective material 

 withdrawn from the blood. 



The discovery of the yellow fever spiral 

 definitely removes the disease from the class 

 believed to be provoked by ultramicroseopic 

 organisms, and at the same time adds so well 

 defined a microbe as Leptospira icteroides to 

 the group of filter passers. The data so far 

 secured regarding this spiral in relation to 

 yellow fever fulfill the conditions arising out 

 of Reed and Carroll's discoveries in connec- 

 tion with the disease in man. These are great 

 gains for theoretical bacteriology. The re- 

 wards to practical medicine are even greater, 

 since it has been found that Leptospira icter- 

 oides lends itself to the making of an active 

 vaccine (killed organisms) and also an eifec- 

 tive therapeutic serum. Hereafter yellow 

 fever is to be combated (1) by removing the 

 breeding places of the stegomyia, (2) through 

 vaccination, and (3) by an antiserum. 



The etiology, or causation, of yellow fever 

 so long and fruitlessly sought seems to have 

 been solved, and it may be of interest to in- 

 quire why just at this juncture? The answer 

 is, through the conjunction of the " prepared 

 mind" and animal experimentation. For 

 nearly a decade Noguchi has been investi- 

 gating this spiral class of microbes, in course 

 of which he added materially to our knowl- 

 edge of methods of study and of new species. 

 He had first-hand knowledge of a related dis- 

 ease, infectious jaundice, transmissible to 

 guinea pigs, which prevails endemically in 

 Japan and sporadically elsewhere, and in 

 which Inada had discovered a peculiar spiral 

 organism (Spirocheta icterohcemorrhagim) ■ In 

 other words, the time was ripe and iN'oguchi 

 peculiarly equipped to take up again and in- 

 vestigate with newer methods the problem of 

 yellow fever. 



The story is still incomplete, as recent de- 

 velopments have shown; for just as Metchni- 

 kofE and Bordet had seen the pallida before 

 Schaudinn, so it now appears Stimson of the 

 U. S. Public Health Service had previously 

 observed the icteroides. He examined a series 

 of sections of organs stained by Levaditi's 

 method to show spiral organisms, taken from 



a patient having yellow fever who succumbed 

 in New Orleans in 1907, and in the kidney 

 found spiral forms to which he gave the name 

 of Spirocheta interrogans, but the significance 

 of which could not then be determined, and 

 which ISToguchi now identifies as the icteroides. 

 Coming at this time and in this way, the ob- 

 servation is a welcome confirmation. "With- 

 out the many data since supplied by Noguchi's 

 experiments and studies of living cases of 

 yellow fever, it possesses only suggestive value. 

 The finding came too early in the develop- 

 ment of our knowledge of the spirochete, and 

 again the seed fell on stony ground. 



There remains one further aspect of this 

 incomplete discussion of spiral microbes in 

 their relation to disease to be considered 

 briefly, namely their separation into two 

 classes according as the diseases induced by 

 them respond to treatment on the one hand 

 by curative serums, and on the other by so- 

 called drugs or chemicals. It has just been 

 stated that yellow fever can be combated by 

 a serum of this kind, and the same is true of 

 infectious jaundice. In this respect the two 

 inciting microbes — L. icteroides and 8. ictero- 

 hcemorrhagice — behave as do certain bacteria. 

 But the spirochete of syphilis and yaws and 

 some others are not subject to serum in- 

 fluences, and hence they and the disease they 

 induce must be attacked from another quarter, 

 and in this instance with chemicals for which 

 they evince an extraordinary selectiveness, as 

 do the malarial organisms and certain para- 

 sitic trypanosomes which are of protozoal 

 nature. 



CHEMOTHERAPY 



Chemotherapy is the name applied to the 

 branch of experimental medicine in which 

 chemicals, or drugs, are searched for, and 

 when necesary and possible, fashioned to sub- 

 due a particular kind or class of infection. 

 The beginnings of chemotherapy reach into 

 the dim past; the science of chemotherapy is 

 just being built up. The epochal discoveries 

 of the curative value of cinchona bark in 

 malaria and of mercury in syphilis, are ex- 

 amples of the early, and as we now say em- 

 pirical working out of specific therapeutics. 



