MILK INSPECTION 2 o$ 



growth of certain bacteria. This condition is absent in the curd 

 from clean milk. 



Feser's Lactoscope. 



This consists of a large, hollow, graduated glass cylinder, into 

 the centre of the base of which is inserted a smaller white glass cylin- 

 der marked with horizontal black lines (Fig. 61). The test with 

 the lactoscope depends upon the amount of dilution of milk required 

 in order that the lines on the inner cylinder be seen when diluted 

 milk is placed in the outer cylinder. The richer in fat, the more 

 opaque is the specimen and the greater the dilution required. 



Thus 4 c.c. of milk are dropped from a pipette through the 

 aperture in the top of the larger cylinder, and water is added in 

 small amounts and thoroughly mixed with the milk by inverting 



Fig. 61. 



Feser's Lactoscope. 



the lactoscope with the finger over the top. When the milk is diluted 

 sufficiently for the black lines on the inner white cylinder to be 

 read, then the percentage of fat corresponds with the figures at the 

 level of the mixture on the larger graduated cylinder (in an upright 

 position). 



As has been stated, the lactometer is unreliable when used 

 alone, but, when employed in conjunction with the lactoscope, quite 

 accurate results may be obtained. While milk which has been 

 skimmed and watered may show a normal specific gravity by the 

 lactometer reading, so milk which is exceptionally rich in fat may 

 be only watered so as to still be within the legal requirements as 

 shown by the lactoscope. By the use of both instruments, either 

 skimming or watering, or both skimming and watering, may be 

 detected — unless the milk is still of average richness. 



