I lO 
PATHOLOGY: H. NOGUCHI 
Proc. N. a. S. 
of adsorption the heat is all liberated in the short span of time during which 
the adsorbed layer is forming. It is therefore obvious that in spite of the 
fact that the heat of adsorption may be greater than that of condensation 
the rise in temperature observed would be mainly due to the oxidation of 
the alcohol as was found by experiment to be the case. 
In view of what has preceded it is to be concluded that the rise in tem- 
perature of the platinum black due to adsorption of the alcohol vapor is 
not the initiator of the reactions which heat the platinum to incandes- 
cence. For the heat generated by adsorption is negligible compared to 
that produced by oxidation and would not be capable of increasing the 
speed of reaction appreciably. 
It is then on the basis of an increased rate of oxidation of the alcoho 
at the surface of the platinum ("catalytic" action) coupled with the phys- 
ical properties of the platinum black that one must explain the rise in 
temperature. In this, one is justified to some extent, for it has long been 
known that surfaces of platinum accelerate certain chemical reactions, 
both in gases and in solution. Recently, Langmuir^ has shown that at 
ordinary temperatures and at reduced pressures platinum foil when "ac- 
tivated" will cause oxygen and carbon monoxide to unite. In this case 
there seems to be some close relation between this action of platinum and 
adsorption, but it is not due to any heating effect. 
1 Langmuir, I., /. Amer. Chem. Soc, Easton, Pa., 40, 1918 (1361). 
2 Zsigmondy, R., Zur Erkenntnis der Kolloide, Jena, 1905 (104). 
LEPTOSPIRA ICTEROIDES AND YELLOW FEVER 
By Hideyo Noguchi 
RocKEPEIivivBR Institute for Medical Research, New York 
Communicated by S. Flexner. Read before the Academy, November 10, 1919 
Although yellow fever is being rapidly controlled by measures directed 
against the intermediate host (the Stegomyia mosquito), which acts as 
the vector, yet the nature of its inciting microbe has remained unknown. 
Hence yellow fever is a striking instance of the fact that given precise 
knowledge of the mode of infection of a microbic disease effective practical 
measures may be evolved for its control, even though the inciting microbe 
remain undiscovered. 
Recently a fresh opportunity was afforded for the investigation of the 
etiology of yellow fever. The International Health Board of the Rocke- 
feller Foundation sent a commission to Guayaquil, Ecuador, in June, 
1918, to survey the field preparatory to the application of measures of 
control. Guayaquil has long been a recognized endemic focus of yellow 
fever, from which periodic extension has taken place to Central America. 
