538 
THOMPSON YATES LABORATORIES REPORT 
bad localities so that practical suggestions might be made to deal with the local con- 
ditions. However, this visit was put off. Unfortunately, however, no arrangements 
were actually made, and, therefore, no suggestions can be made. By repute several 
places which were very fatal to early pioneers are now regarded as comparatively 
healthy ; even if this be true the possibilities are too numerous and vague to make 
discussion profitable. 
Elsewhere the question of the clinical condition of the superficial lymphatic 
glands is raised, and it may be repeated here, since if enlargement does not occur, 
for instance, in the axillary glands in malarial, but not yellow fever districts, the 
point may be of some use in the diagnosis of yellow fever, especially in mild cases, 
and perhaps also in malarial individuals. 
It may be of interest to mention that quite a number of Brazilians (medical and 
lay) hold that malarial attacks are apt to occur at monthly intervals, some even go 
so far as to consider that the moon is the directive force. 
Some vise was made of the centrifuge to assist in the discovery of malarial para- 
sites. The scheme was to take about three volumes of blood into a capillary (such 
as one ordinarily uses for sedimentation tests) containing about one volume of 
citrated salt solution (one per cent, citrate of soda giving eventually one-quarter per 
cent., which prevents coagulation) ; after mixing well, the tube is sealed at the end, 
and centrifugalized for a few minutes. Three layers are obtained, supernatant 
plasma (with many suspended platelets), protoplasmic layer (containing leucocytes, 
platelets, and crescents), if present in the blood, red corpuscle layer. In a warm 
climate, if the tube is kept some time before it is centrifugalized, the leucocytes may 
have crawled about on the glass, and thus make an unduly thin layer above the red. 
By cutting off the tube just above the leucocyte layer, the leucocytes and upper 
layers of red layer may be removed with fine capillary and examined. For making 
permanent preparations, it is best to fix rapidly, as by placing the films at once into a 
petri dish into which a drop of strong formalin has been put ; red corpuscles are apt 
to crenate more rapidly from the diluted plasma than from plain blood. The 
leucocyte layer forms an easy means of detecting pigmented individuals, and thus 
assisting diagnosis, and also gives concentrated specimens where it is desired to make 
differential counts of the varieties of leucocytes. We also tried using a fixing fluid 
for the dilution, such as saline solution, with a trace of corrosive sublimate, naturally 
the proportion of blood taken must be less, otherwise clotting will occur. • 
Yellow Fever and Ague. It has sometimes been stated that there is some 
antagonism between the two diseases. Out of our seventeen autopsies, in four cases 
there were malarial spleens ; one of these is interesting, and is in accordance with 
the chances of infection. The patient was a Bolivian soldier who got malaria up 
river on his passage over from his home country ; a few days after arrival in Para he 
contracted fatal yellow fever. So far as Para is concerned, an immigrant coming 
