SECTION IV., 1910. [41] Trans. R.S. C. 
IV.—Upon the Number of Micro-Organisms in the Air of Winnipeg. 
By A. H. R. Buzzer, D.Sc., F.R.S.C., and Cas. W. Lowe. 
(Read September 28, 1910.) 
INTRODUCTION. 
The authors have determined the number of micro-organisms 
present in the air of Winnipeg during every week throughout a whole 
year. Hitherto, no statistics of this kind have been compiled for 
Central Canada, and it was thought that the investigation might pos- 
sibly have some bearing on the spread of certain diseases in addition 
to its general biological interest. 
As long ago as 1887 Frankland! published a curve showing the 
seasonal variation in the number of micro-organisms in the air of London. 
The English climate, as is well known, is very humid; and the winters 
are usually wet and mild. In contrast with this, the climate at Winni- 
peg on the whole is very dry, especially during the winter. Whereas 
in England snow covers the ground for only a few weeks in the year, 
at Winnipeg the ground is frost-bound and covered with snow for 
something like five months. The difference in the climate of the two 
places, therefore, is very marked; and, as we shall see, a comparison 
of Frankland’s observations with those made by us shows how greatly 
the distribution of micro-organisms is affected by climatic conditions. 
Those who live in Manitoba are aware how very free the air is 
from dust particles during the winter months. On account of the 
dustlessness of the atmosphere, it was expected before the investiga- 
tions began that, at this period of the year, there would be a very small 
number of micro-organisms in the air of Winnipeg relatively to that 
of London as determined by Frankland. This expectation has been 
fully realised; and for healthiness, so far as the number of micro- 
organisms is concerned, the climate of Central Canada during the win- 
_ ter must be one of the best in any civilised country in the world. 
Among earlier workers upon the distribution of micro-organisms 
in the air may be mentioned Pasteur, Miquel, Hansen, Fischer, Moreu 
& Miquel, Minervini, Giacosa, Miflet, Selander, Cacace, Shibuya, and 
Frankland. Recently, Saito,? using the plate method, has carried out 
? P. F. Frankland. Furthér Experiments on the Distribution of Micro-organ- 
isms in Air (by Hesse’s Method). Proc. of the Roy. Soc., Vol. 42, 1887, pp. 267-282. 
? K. Saito. Untersuchungen über die atmosphärischen Pilzkeime, The Journal 
of the College of Science, University of Tokyo, Vol. xxxvii, 1904, pp. 1-58. 
