Some effects of the source of bovine milk leucocytes and strain of staphylococcus on their interaction in vitro.

A METHOD IS DESCRIBED FOR THE QUANTITATIVE STUDY IN VITRO OF THE BOVINE MILK LEUCOCYTE: staphylococci interaction which is capable of demonstrating differences between groups of leucocytes, and, to some extent, stains of Staph. aureus. By means of this method it has been possible to show statistically, that significant differences can occur, between quarters of the same udder, in the numbers of leucocytes competent to ingest staphylococci, and also in the numbers of staphylococci ingested. Between 4 strains of Staph. aureus significant differences were noted in their ability to multiply in the presence of milk leucocytes; in the production of leucocidal factors; and in the reduction of Resazurin in whole, normal milk.