CONTROL OF SEPARATORS. 261 



as happens most frequently in the winter, it may be distinctly 

 brown. 



This by no means consists, as is often considered, of dirt and 

 cow-dung, though it naturally contains these impurities if present 

 in the milk. Microscopical examination shows it to contain — 



1. Inorganic impurities — i.e., dust gathered during transport, 

 and earthy matters due to uncleanliness. 



2. N'egetable matters derived from the dust of the food given 

 to the cattle — e.y., bark of hay, fine particles of cake, etc. ; in 

 many cases portions of leaves with stomata developed may be 

 identified. Other portions of the vegetable matter have the 

 cell walls considerably disintegrated ; these have probably passed 

 through the alimentary tract of the cow, and indicate the presence 

 of cow-dung. 



.3. Substances derived from the cow ; hairs are often found ; 

 much epithelium from the udder of the cow, and possibly also 

 from the hands of the milkers ; and empty sacs (gland cells), 

 which form a very laif^fc portion of the slime. (If the cow was 

 in ill-health, mucus, blood, and pus may be present.) 



Micro-organisms are very numerous ; should the cows be 

 afflicted with tuberculosis of the udder. Bacillus tuberculosis 

 may l)e found here. 



The following composition is assigned to separator slime by 

 the author and by Fleischmann, respectively ; — 



It is doubtful whether the substance returned as casein is 

 wholly this body ; it is undoubtedly a mixture of several pro- 

 teins, including Storch's mucoid protein. 



The following is the composition of the ash : — 



Total ash, . ... 3-01 per cent. 



Soluble ash, . 0166 „ 



Insoluble ash, . . 2S44 „ 



consisting of 



Silica, . . 0171 per cent. 



Iron oxide and alumina, 0-012 „ 



Lime, . . 0-654 



Magnesia, . 0-225 



AlkaUes, . . . ^'-559 



Phosphoric anhydride, . . . 1-233 „ 



