﻿EXPERIMENTS IN MALARIAL TRANSMISSION. 531 



passage of the parasites to the salivary glands might be traced. By this 

 means their presence in all the intervening tissues between the stomach 

 and the salivary glands was demonstrated. The accompanying photo- 

 micrographs (PL IX, figs. 2, 3, and 4, and PI. X) show them also in the 

 interstices between the muscle-fibers of the thorax, and in the salivary 

 glands themselves. 



Appearance of the sporozoites. — Specimens stained with hsematoxy- 

 lin-eosin, prepared according to the ordinary formula, show the normal 

 muscular, glandular, and connective tissues stained red or blue, while 

 within the cell structure itself innumerable, extremely small granules, 

 either globular or elongate, appear, measuring not more than 0.75 fi in 

 diameter and of a dark brown color. They are not only found within 

 the cells of the tissue, but also, as is shown by certain salivary glands 

 examined, adherent to the external walls of the gland cells. This phe- 

 nomenon is shown in Plate IX, fig. 4, at the point marked spor. 



TRANSMISSION OF THE PARASITE. 



Upon going to Olongapo, it was not my intention as it was not my 

 hope to procure volunteers who would be willing to submit to being 

 bitten by mosquitoes infected with malarial organisms, so that I said 

 nothing except in a suggestive way to the gentlemen in charge of the 

 medical work at this station, until I had reached to the stage of demon- 

 strating the oocysts in the stomach wall of the mosquito. Finally I 

 obtained one volunteer, the result being as follows : 



Case I. Volunteer malarial infection. — J. C. B. had been in the Philippines 

 nearly two years; his medical history during his six years' service in the Navy 

 gave no indication of his ever having had malaria. His statements were also 

 to the effect that he had never had malaria, chills and fever, or any illness that 

 would point to his having been infected. Many examinations of his blood demon- 

 strated continuous absence of malarial parasites. 



The patient was first bitten by a malaria-infected mosquito at 5 p. m. of June 

 1, 1907. This mosquito did not draw any blood, after having repeatedly thrust 

 its proboscis into the patient's arms at different points. On the morning of June 

 2 at 8 he was again bitten by the same mosquito and by two others which were 

 confined together in another tube. At 10.30 on the morning of June 3, at 10.30 

 a. m. of June 4, and at 8.30 a. m. of June 6 he was rebitten by the same three 

 mosquitoes, they having had no other alimentation beyond that furnished by his 

 blood. Every day, except on June 8, he showed a slight rise of temperature, but 

 never above 37.4° C. On June 9 the patient complained of malaise, severe head- 

 ache and chill, which latter was not very marked. Temperature at 12 o'clock, 

 38.3° C. In the evening the patient again felt well and during the next day his 

 temperature was practically normal. On June 11 the temperature rose to 38° C, 

 the patient having a slight chill, although he did not lie down nor desist from 

 his routine work. From June 11 until the time of my departure, he had no 

 further rise of temperature and no chill; he, however, continued his chart up 

 to and including July 6. It shows that on June 24 he had a slight chill and 

 that on the next day his temperature was 37.7° not rising again until June 28 

 when it reached 38° C, and again on July 2, 38.2° C. On July 1 the patient 

 had headache, nausea, and general listlessness, with loss of appetite and frequent 

 dizzy spells. On September 4 he reported as follows: "I had a spell of fever 



