Abstract: There is disclosed a method for the quantitative determination of mastitis in a cow. This method comprises decaseinating and delipidating a milk sample from the cow to obtain a clear solution, substantially removing .alpha..sub.2 -macroglobulin from the sample, mixing the clear and substantially .alpha..sub.2 -macroglobulin free sample with a known amount to trypsin, and measuring the activity of the amount of trypsin which is in excess of the amount which is inactivated by the milk's antitrypsin.

Abstract: The subject of the present invention is a photometer, which comprises a source of light (5), from which the measurement light is arranged to be passed through a lens (6) and a filter (7) onto a semi-transparent mirror (8) placed on the path of the light preferably at an angle of 45.degree., the reference beam of light (9) being arranged as passing through the said mirror onto a reference detector (11) and the measurement beam of light (10) reflected from the said mirror being arranged as passing to the measurement detector (12). According to the invention, the said source of light (5), lens (6), filter (7), semi-transparent mirror (8), and the reference detector (11) and the measurement detector (12) are placed in an optics frame (4) of one piece, the said optics frame being movable in relation to the frame and case part (1) of the photometer along one or several guides (2, 3).

Abstract: An oscillator operating within the frequency and with the wave shape selected for the operation of the device cooperates with transmitter strips of a length of the desired distance of indication of the movement and formed, e.g., in the way of printed circuits as connected to the said oscillator, as well as corresponding receiver strips as connected to a differential amplifier, e.g. to the amplifier of an integrated circuit. Hereinafter it is possible, by means of the indicator, to indicate a connecting together of the transmitter strips and the receiver strips by means of mobile plates placed on the device whose position is supposed to be indicated.