──────────────────────┬──────────────────────────── │ Prepared from ──────────────────────┼──────────────┬──────────── │ Mares' Milk. │ Separated │ │ Cows' Milk. ──────────────────────┼──────────────┼──────────── │ Per Cent. │ Per Cent. Water │ 91.535 │ 88.933 Fat │ 1.274 │ 0.854 Nitrogenous bodies │ 1.913 │ 2.025 Sugar │ 1.253 │ 3.108 Ash │ 0.293 │ 0.444 Carbon dioxide │ 0.876 │ 1.027 Alcohol │ 1.850 │ 2.647 Lactic acid │ 1.006 │ 0.796 Glycerine │ .... │ 0.166 ──────────────────────┴──────────────┴──────────── Fleischmann[63] gives a formula for preparing an artificial koumiss from separated cows' milk, water, cane sugar, and milk sugar, with the addition of distillery yeast. Needless to say, this product must possess some of the characteristic by-flavour of the yeast employed, and is less suitable than koumiss prepared by the aid of a lactic yeast. Schipin investigated the fermentation of koumiss and found three distinct organisms. Rubinsky in a recent article threw much light on the phenomena of koumiss fermentation. According to him, koumiss contains almost invariably four different organisms, viz., koumiss yeast, koumiss bacterium (_Lactobacillus_), _Streptococcus lactis_ (Lister), _Bacterium aërogenes_, and occasionally _Bact. caucasicum_ (Nikolajewa). For the preparation of normal koumiss only the two former organisms are required; they exceed in number any of the other organisms whose presence in the dairy is unavoidable. The presence of the two latter organisms is favourable to the production of good koumiss, as, by inducing a preliminary lactic fermentation, they tend to inhibit the growth of undesirable extraneous bacteria, etc. In medium and strong koumiss they die out on account of the amount of lactic acid formed (1%). Koumiss yeast possesses strongly differentiated protoplasm, but lacks any cultural characteristics. Abundant growth occurs in milk, and lactic acid (0.3%), alcohol, carbon dioxide, albumens and peptones, volatile acids, and aromatic substances are formed. Koumiss bacterium is related to the _Lactobacillus_ of various other fermented milks, and is similar to _Bac. acidophilus_, and possesses like these a distinct polymorphism (branched cells, long and short bacilli, etc.). It is non-sporogenous, has an optimum temperature of 90° to 97° F., and possesses cultural characteristics similar to those of the rest of the _Lactobacilli_. The by-products of koumiss yeast appear to favour the growth of the koumiss bacterium, as this organism, like the other _Lactobacilli_, is favourably influenced by the presence of small quantities of peptone, alcohol, and acid.