5 
reaction, neither did they give a definitely negative one, i.e., a cloudiness 
could not be produced either by the addition of more blood or of more 
serum, or by prolonged agitation, or even by repeating the test. This was 
attributed to the fact that these samples were too dilute. These eight 
are not included in the data. These naked eye tests were made in the 
field, generally within a few hours of collecting the sample, and invariably 
within the space of forty-eight hours. On my return to Winnipeg, which 
was within six weeks of taking the first sample of blood and within a fort- 
night of the last, all samples were subjected to a microscopical test by an 
experienced technician. He employed the unused sera brought back 
from the field, for they were found to be still very active. 
It is worthy of note that though twenty-one positive naked eye 
reactions were obtained in the field, I was unable on my return to Winnipeg 
to reproduce any one of these in the laboratory, nor, except in three 
instances, did the technician, who was controlling my findings, observe under 
the microscope any agglutination of cells. The three samples he found to 
react were among the last taken. He re-tested these daily for a week, by 
the end of which time each of the three had ceased to respond. This was 
explained by the fact that every specimen was completely or partly 
haemolysed, as could be seen from a naked eye inspection of the blood 
samples. 
In order to determine whether or not haemolysis would take place 
under slightly more favourable circumstances samples of blood from indi- 
viduals belonging to groups 2 and 3 were collected in tubes of forma- 
lin citrate solution obtained from different sources. These were placed 
exposed to light on the laboratory shelf, on November 19, 1928, and were 
examined at intervals of one week. One set failed to agglutinate by 
January 9, 1929, the other by January 21, 1929; that is, within a period of 
two months after collection. It w r ould appear from this that it is prudent 
to test samples as soon after collection as possible, which usually is while 
still in the field. 
Material 
In all, observations were made on two hundred and thirteen Indians, 
who were distributed as follows: 
Adult and Old Male Chipewyan Indians 
F ond-du-lae Adult (ages 20-59 years) 33 
Old (ages 60 years and over) 0 
Total number examined 33 
i.e., 38 per cent of the total adult male population of 87. 
Chipewyan Adult (ages 20-59 years) 15 
Old (ages 60 years and over) 6 
Total number examined 21 
i.e., 31 per cent of the total adult male population of 67. 
Fitzgerald and Fort Smith . . . Adult (ages 20-59 years) 24 
Old (ages 60 years and over) 0 
Total number examined 
24 
