_Matzoon._—This is a drink used largely in Western Asia, and is similar in character to keffir, but has a peculiar taste which distinguishes it from all other fermented milks. According to Weigmann,[66] it is prepared from buffaloes', goats', or cows' milk, and is used partly as a means of souring milk for butter-making and also as a lactic food, eaten with spoons. In the same way buttermilk produced from milk which has been previously ripened by matzoon is used as a beverage. Finally, the coagulum (_than_) of such buttermilk is strained off, and, after being pressed, is mixed with meal and dried by exposure to the sun's rays. The preparation of matzoon is in many respects very similar to that of keffir and koumiss, but differs by inducing a comparatively weak alcohol fermentation. In common, too, with yoghourt, the prevailing temperature is much higher than is required for keffir and koumiss. In regard to the biology of matzoon, the occurrence of various organisms has been recorded. Emmerling[67] isolated, in addition to a yellow pigment-forming organism, _Bacillus subtilis_, _Bacillus lactis acidi_, and several fungi, a small micrococcus capable of hydrolysing milk- and cane-sugar. The organism produces and without gas formation, or peptonisation of the medium. Of the nine yeasts isolated from matzoon by Lindner[68] and Kalantharianz,[69] three were able to ferment milk sugar without previous hydrolysis, while two others, by the simultaneous production of lactic acid and fruit esters, gave to the matzoon its characteristic taste and aroma.