Published online by Cambridge University Press: 01 June 2009
The chemical method of Tolle, Zeidler & Heeschen, (1966) for dispersing the fat in milk to allow electronic counting of the cells in suspension has been examined. The optimum conditions prescribed for obtaining the best estimates of cell counts were largely confirmed though inaccurate counts occasionally occurred. The reproducibility of counts made on the same milk samples was acceptable. For milk samples from individual quarters, cell counts determined after the chemical treatment and those after centrifugal separation of the fat could be related by a linear regression line of unit slope through the origin. The surface active liquid Lissapol NXP (I.C.I. Ltd.) appeared to be a suitable substitute for the Witopal CO (Chemischen Werken in Witten/Ruhr), an alkylphenol polyglycol ether, used by Tolle et al. (1966).