81 
indicating older parasites with amoeboid motion. These latter were 
two or three times the size of the small ring forms. (See plate 2.) 
These irregularly shaped parasites had two and some three chro¬ 
matin points. In the blood taken at subsequent periods similar forms 
were seen, the older or younger forms predominating, depending upon 
the time of day the blood was examined. 
The details of diluting and filtering the blood serum of Filomena 
Martinez follow : 
At 5.30 p. m. the blood was taken from the ice chest-, having been 
there just five and one-half hours, and 27 cc. of the clear serum were 
pipetted off. This serum contained a few flakes and very few red 
blood cells. 
To this serum was added an equal amount (27 cc.) of physiological 
salt solution (0.6 per cent). 
The mixture was transferred to a filter flask and a Chamberland B 
filter was carefully lowered into the fluid and securely fastened in 
position. This was a new filter marked as follows: “B. filtre Cham¬ 
berland systeme Pasteur H. B. Cie., Choisv-le-Roi. BTE S. 6.O.G. 
Con tr ole.” 
The filter was tested before using with an air pressure of 30 pounds, 
after which it was lowered into water. When first lowered into the 
water the air came froni every part of the surface of the filter in very 
fine bubbles, but nowhere was there evidence of a crack or pinhole. 
As soon as the filter became wet no air could be forced through it 
with a pressure of 30 pounds. This particular candle was consid¬ 
ered to be tighter than the other Chamberland-Pasteur filters which 
we had similarly tested. 
The filter was then thoroughly washed by allowing 200 cc. of water 
to pass through it under 20 pounds pressure. It was sterilized in the 
hot air sterilizer for one hour on the day before the blood was filtered, 
at a temperature of 150° C. for one hour. 
The filtration was begun at 6 p. m., October 27, and was conducted 
in accordance with the diagram (fig. 2) by means of pressure from 
an air pump. This air pump was worked by hand and the diluted 
blood serum filtered under a pressure of 15 pounds. The pressure was 
controlled by the gauge, as shown in the sketch. 
Very slight variations occurred both above and below 15 pounds, 
owing to the difficulty of exact control with hand power. 
The pressure was kept up for one hour, and the filtrate was drawn 
from the inside of the bougie with a long sterilized pipette. In this 
manner it will be noticed that there was no possible chance of contact 
between the filtrate and the blood serum, and throughout the process 
the greatest care was taken in order to prevent such a contamination. 
The filtrate as it came through the filter was clear and of amber 
color. 
