This must not be understood, however, as asserting that all the milk drawn from the udder at one milking is contained in the receptacle. The milk, as it is secreted, is conveyed to the receptacle, and when that is full, the larger tubes begin to be filled, and next the smaller ones, until the whole become gorged. When this takes place, the secretion of the milk ceases, and absorption of the thinner or more watery part commences. Now, as this absorption takes place more readily in the smaller or more distant tubes, it is invariably found that the milk from these, which comes last into the receptacle, is much thicker and richer than what was first drawn off. This milk has been significantly styled afterings, or strippings; and should this gorged state of the tubes be permitted to continue beyond a certain time, serious mischief will sometimes occur; the milk becomes too thick to flow through the tubes, and soon produces, first irritation, then inflammation, and lastly suppuration, and the function of the gland is materially impaired or altogether destroyed. Hence the great importance of emptying these smaller tubes regularly and thoroughly, not merely to prevent the occurrence of disease, but actually to increase the quantity of milk; for, so long as the smaller tubes are kept free, milk is constantly forming; but whenever, as has already been mentioned, they become gorged, the secretion of milk ceases until they are emptied. The cow herself has no power over the sphincter at the end of her teat, so as to open it, and relieve the overcharged udder; neither has she any power of retaining the milk collected in the reservoirs when the spasm of the sphincter is overcome. Thus is seen the necessity of drawing away the last drop of milk at every milking; and the better milker the cow, the more necessary this is. What has been said demonstrates, also, the impropriety of holding the milk in cows until the udder is distended much beyond its ordinary size, for the sake of showing its capacity for holding milk--a device to which many dealers in cows resort.