If the relative humidity goes too high, the surface slime of bacteria and yeasts becomes very heavy, soft and almost liquid, and follows the openings into the cheese with resultant damage to appearance and flavor. Even under the conditions at Roquefort, this slime must be removed by rubbing or scraping several times to avoid injury to the cheeses, together with the production of bad odor and taste. If the humidity becomes too low, the surface becomes dry, hard and cracks open, the friable crumbly texture is injured, and there is considerable loss in weight. Salt forms about 4 per cent of the cheese. This is in solution in the water present, which is about 40 per cent, and makes a brine of about 10 per cent strength. This strength of brine does not prevent the growth of the Roquefort mold (_Penicillium Roqueforti_) but does hinder the development of _Oidium lactis_ in the open spaces within the cheese. Accurate adjustment of temperature and relative humidity in the ripening rooms to salt and water-content in the cheese is essential to proper ripening. These conditions are furnished by the unique natural conditions of the caves of Roquefort. The production of such cheeses elsewhere depends either on the discovery of another locality with closely similar conditions or on the artificial production and control of the necessary temperature and relative humidity. This has been done on an experimental basis by the use of cold storage apparatus combined with proper humidifiers. The differences between working with sheep's and with cow's milk lie in the making process rather than in the ripening. Sheep's milk freshly drawn shows a higher acidity than cow's milk, probably on account of the acid reaction of its greater casein content. With nearly double the total solids of cow's milk, the yield to one hundred pounds is much greater, consequently the drainage of the curd is much more easily handled. Once made and salted, the cheeses require very nearly the same conditions of ripening. The resultant products are alike in appearance and texture. In flavor, cow's milk Roquefort differs in character from sheep's milk cheese to such a degree as to be recognized by taste. The difference was found by Currie[73] to be due to an actual difference in the combination of fatty acids present. Although these differences in character are recognizable by the expert in testing the cheese, as well as by chemical analysis, cow's milk Roquefort would satisfy that large proportion of consumers who use such cheese only in connection with other fairly high flavored foods. The demands for technical skill and factory equipment are not naturally greater than for many other lines of cheese-making. The gradual development of a cow's milk Roquefort may be anticipated. [Illustration: FIG. 24.--Gorgonzola ripening establishment in valley near Lecco.]