104 



the whole blood was used it was quickly added while fresh to melted 

 agar, at 42° C. , in the proportion of about 2 parts of blood to 1 of agar. 

 After mixing, the tubes were slanted and allowed to set. The defibri- 

 nated blood was prepared by whipping in the usual way, and then it 

 was added to the melted agar in about the same proportions as above 

 stated. After standing a short while the blood-agar slants, thus pre- 

 pared, developed from several drops to about 1 cc. of "water of con- 

 densation." 



A drop or two of blood from typical cases of yellow fever taken from 

 the arm vein during the early stages of the disease was planted into this 

 "water of condensation." 



Other cultures were prepared with much larger quantities of the 

 yellow fever blood, using the yellow fever blood itself as a part of the 

 culture medium. To tubes containing about 2 cc. of melted agar, about 

 4 cc. of fresh yellow fever blood was added as quickly as possible after 

 its withdrawal from the vein. Other tubes were similarly prepared 

 with the defibrinated yellow fever blood. 



Some of the cultures were kept in the incubator at 37° O, and others 

 at room temperature. Of the latter, some were kept in the dark and 

 others exposed to the light in order to simulate the conditions as they 

 appear to occur in the mosquito. 



The, water of condensation was examined from time to time both in 

 hanging drop and in stained smears. It was found to contain large 

 numbers of bodies of various sizes and shapes, some of them exhibiting 

 curious and exaggerated Brownian motion. All of the particles were 

 interpreted as degeneration products, mostly from the cellular ele- 

 ments of the blood. 



