﻿ETIOLOGY OP DENGUE FEVER. 117 



4. INTRAVENOUS INOCULATION WITH UNFILTERED DENGUE BLOOD. 



Eleven of our fourteen volunteers were given intravenous inoculations 

 of unfiltered blood from dengue patients*, and of these, seven developed 

 the disease, while in one case the result was doubtful. In three of the 

 cases there existed, apparently, an absolute immunity to the disease. 

 These cases will now be considered in detail. 



Experiment No. 1. 



Case 1, Chart 1. — E. TJ., private. Hospital Corps. United States Army. Had 

 not been exposed to dengue. At 3.30 p. m., July 24, 1906, lie was given an 

 intravenous injection of 20 minims of unfiltered blood from Case 20 (see Chart 

 A ) . The patient from whom the blood was taken for the inoculation had a 

 mild attack of dengue and was probably nearly over the disease at this time. We 

 believe that this accounts for the mild character of the experimental disease in 

 this case, for while the symptoms which were present were typical, it will be seen 

 on referring to the temperature chart that the fever was slight as compared with 

 our other experimental cases, which were all inoculated with blood from more 

 severe cases, taken at an earlier period of the disease. The following is a resume 

 of the clinical record in this case: 



July 24: At 3.30 p. m. inoculated intravenously with 20 minims of blood from 

 Case 20. Subject in good health and temperature normal. 



July 25: Feels perfectly well. 



July 26 : Feels well. No symptoms. 



July 27: Ditto. 



July 28 : Has some fever and headache. Bowels constipated. 



July 29: Patient feels uncomfortable, complaining of vague muscular pain 

 and burning and smarting of eyes; eats and sleeps fairly well. Bowels regular. 



July 30: Last night felt very uncomfortable, having severe headache and pain 

 in eyes ; also pain in the lumbar muscles, ankles, elbows and wrists. At present 

 (11 a. m.) complains of dull headache and slight lumbar pain; the eyes are 

 painful, the pain being aggravated by movement. Tongue moist and clean. 

 Bowels constipated. 



July 31: Feels much better, the pains in the head and muscles having dis- 

 appeared. A slight eruption is present upon the chest and back. 



August 2: Feels well. Eruption has faded. 



August 6 : Returned to duty. 



Remarks. — Upon reference to the temperature chart (Chart 1) it will be 

 observed that the temperature began to ascend about 9 a. m. on July 28, but 

 the patient complained of no symptoms until nearly twenty-four hours later. 

 The incubation period in this case, therefore, is about three days and eighteen 

 hours, reckoning it from the 9 a. m. temperature on July 28. 



Experiment No. 2. - 



Case 2, Chart 2. — W. R. H., private, first class, Hospital Corps. Not previously 

 exposed to dengue so far as known. In good health. At 11 a. m., July 31, 1906, 

 was given an intravenous inoculation of 20 minims of blood from Case 30 (Chart 

 B), who was suffering from a typical attack of dengue of four days' duration 

 at the time the blood was obtained. No symptoms appeared in Case 2 until 

 early in the morning of August 3, as is shown by the following resume of the 

 clinical record: 



July 31: Inoculated with dengue blood as stated. 



August 1 and 2: Feels well. 



