492 
beyond which the milk was regarded as unfit for use. In other 
words, it was only a question to what extent the evil was to be 
endured. The present views concerning cellular elements in cows* 
milk are somewhat different. 
Histologists long ago pointed out that leucocytes occur in milk,, 
when the gland structure showed no evidence of inflammation. Co- 
lostrum corpuscles are regarded as leucocytes loaded with debris of 
gland cells removed to clear up the channels for milk flow. It seems 
but natural that such a remarkable and rapid metabolic process as 
milk formation should be accompanied by a large number of leuco- 
cytes. In fact, in sections of normal functionating mammary glands 
they are found to be numerous in the capillaries and in the connective 
tissue spaces between the alveoli, from which they make their way 
between the gland cells and appear in the milk. 
As regards leucocytes and pus cells there is no intrinsic difference. 
A leucocyte in fluids other than blood plasma — as milk, for example — 
soon undergoes changes which render it indistinguishable from a pus 
cell. That pus does occur in milk from inflamed mammary glands 
need scarcely be mentioned. Before considering further the signifi- 
cance of leucocytes, it will be of interest to note the various methods 
used for counting them. Stokes and Wegefarth® were the first to 
attempt an enumeration. Briefly, their method consisted in cen- 
trifuging a definite quantity of milk, spreading the entire sediment 
on a slide over a definite area, staining and examining with a T y-inch 
lens ; the number of leucocytes in ten or more fields of the microscope 
was noted, and an average struck. From this data an estimate was 
made of the number per cubic centimeter. 
Stewart b and Slack 0 used a refinement of the same method. 
Doane-Buckley d modified the procedure in common use for counting 
blood cells, employing the Thoma-Zeiss instrument, with quite accu- 
rate results. 
Savage 0 used a very similar method. Still another way of estimat- 
ing the leucocytes is based on a procedure applied to blood — the use of 
a modified hematocrit, in which the milk is centrifuged and the leuco- 
cytes read on a scale, as sediment in volume per cent. Trommsdorff, f 
in Germany, has perfected this method. As might be expected differ- 
ent methods give widely different results. Bergey^ in a recent paper 
records a number of comparative counts by the Stokes, Stewart, 
a Medical News, 1897, No. 91, p. 45. 
& American Medicine, 1905, No. 9, p. 486. 
c Journ. of Infect. Diseases, 1906, Sup. No. 2. 
d Maryland Agric. Exper. Station, 1905, Bull. 102. 
«Brit. Med. Jour., 1905, No. 1, p. 1165. 
/Munch. Med. Woch., 1906, No. 53, S. 541. 
^Univ. of Pa. Med. Bull., 1907, vol. 20, Sept. 
