Observations by anoptral contrast microscopy of casein in milk, condensed milk and milk powder

Anoptral contrast, a modification of phase-contrast microscopy, appears to be suitable, particularly perhaps when used in conjunction with fluorescence microscopy, for studying casein particles above 0·1–0·2μ in diameter, and different aggregation and coagulation forms of casein, which may comprise irregular flocks of aggregated particles, thin membranes and micro-fibres, nodulated or smooth.