The Significance of Leucocytes and Streptococci in the Production of a High-Grade Milk

A correlation of the finding of streptococci or of many leucocytes in milk by the laboratory, with the physical condition of the cows in a herd maintained for the production of a very clean milk, would seem to show that in many cases there is a connection between such findings and the condition of the cow, both in relation to specific udder and to systemic affections. Such parallelism seems to obtain for the end of the lactation period, for the beginning of an udder inflammation, for an attack of cow pox, and, possibly, for chemotactic conditions due to high feeding of animals constitutionally unable to transform the increased feed into increased milk. The frequent laboratory examination of the milk of individual cows has materially assisted the herdsman in preserving the good health of the animals and has stimulated more frequent and careful clinical observations. It is believed, too, that such examinations are a very material factor in maintaining a bacterial count which, for the past 13 months, averages 3,267 organisms per c.c. when the milk is from 26 to 40 hours old. Our cordial thanks are due to Dr. E. Q. St. John, who has most ably assisted in the microscopic and bacteriological work needed for this paper.