﻿ETIOLOGY OF DENGUE FEVER. 123 



Experiment No. 8. 



Case 8, Chart 8. — R. R., private, Company H, Thirteenth Infantry. This 

 man was in good health at the time of volunteering, but had been exposed to 

 dengue during the epidemic at Fort William MeKinley. The following is a 

 clinical record of the case: 



September 12: Inoculated intravenously with one-half minim of blood from 

 Case 83 (Chart 0), who was suffering from a typical attack of dengue. 



September 15 : Patient states that he had a severe headache last night, com- 

 mencing at midnight. Still complains of headache and pain in the arms.- 



September 16: Still complains of headache, but has no other pain. Bowels 

 constipated, appetite poor. 



September 17 to 19: Patient is feeling well. 



September 19: Inoculated intravenously at 1 p. m. with 1 cubic centimeter of 

 filtered blood from Case 1 1 ( Chart 11). No result. 



September 25 : Inoculated intravenously at 1 p. m. with 20 minims of blood 

 from Case 38 ( Chart D ) . No result. 



Remarks. — We have regarded this case as doubtful, although we are inclined 

 to believe that the rise of temperature upon September 15 was due to a slight 

 attack of dengue produced by the inoculation of one-half minim of dengue blood. 

 This is much less blood than we have used in our other experiments and it may 

 be that the slight symptoms produced are due to this fact. If this man did not 

 suffer from an attack of dengue during his first inoculation he must have been 

 immune, as neither the subcutaneous inoculation of filtered blood or the intra- 

 venous inoculation of unfiltered blood produced any result. ' 



Summary. — The intravenous inoculation of unfiltered dengue blood 

 into healthy men is capable of producing a typical dengue attack in such 

 men. Thus, of eleven men so inoculated, seven suffered from dengue 

 fever produced in this manner, while in one the result was doubtful. 

 Three of the men were immune to the disease after inoculation. 



5. INTRAVENOUS INOCULATION OF FILTERED DENGUE BLOOD. 



Having proven by our inoculation experiments with unfiltered blood 

 from dengue patients that the disease could be thus transmitted and, 

 furthermore, that while the cause must, therefore, be present in the 

 blood, it is not possible to demonstrate it in either fresh or stained 

 specimens by any known method of examination, we are forced to the 

 conclusion that the causative organism must be ultramicroscopic, as in 

 the case of yellow fever, rinderpest, etc. 



The most important diseases which have been proven to be due to a contagion 

 which passes through porcelain or diatomaeeous filters are foot-and-mouth dis- 

 ease, pleuro-pneumonia of cattle, yellow fever, rabies, rinderpest, South African 

 horse sickness, and hog cholera. 



Loeffler and Frosch (26), in 1898, discovered that the cause of foot-and-mouth 

 disease in cattle passed through the pores of a Berkefeld filter which restrained 

 other well-known bacteria ; Nocard and Roux ( 27 ) , in the same year, proved that 

 the organism causing the pleuro-pneumonia of cattle passed through a Ber-kefeld 

 and Chamberland F filter, but not through a Chamberland B; they were also 

 successful in cultivating the organism by the collodion-sac method, but as they 



