Attention must be paid to the temperature of the food when given to the infant, which ought to be as nearly as possible the same as that of the mother's milk, namely from 90 deg. to 95 deg. Fahrenheit, and in all cases in which care is needed a thermometer should be employed in order to insure the food being given at the same temperature. Human milk is alkaline, and even if kept for a considerable time it shows little tendency to become sour. The milk of animals when in perfect health likewise presents an alkaline reaction, and that of cows when at grass forms no exception to this rule. Milk even very slightly acid is certain to disagree with an infant; it is therefore always worth while the moment that a hand-fed infant seems ailing to ascertain this point. If alkaline, the milk will deepen the blue colour of litmus paper, which is to be had of any chemist; if acid, it will discharge the colour and turn it red. It is, perhaps, as well to add that, as the oxygen in the atmosphere tends to redden litmus paper, it should not be left exposed to the air, but should always be kept in a glass-stoppered bottle. The milk of the cow is very liable to alteration from comparatively slight causes, and particularly from changes in the animal's diet; while even in the most favourable circumstances if the animal is shut up in a city and stall-fed, all the solid constituents of its milk suffer a remarkable diminution; while the secretion further has a great tendency to become acid, or to undergo even more serious deterioration. Mere acidity of the milk can be counteracted for the moment by the addition of lime-water, or by stirring up with it a small quantity of prepared chalk, which may be allowed to subside to the bottom of the vessel; or if it should happen, though indeed that is rarely the case in these circumstances, that the child is constipated, carbonate of magnesia may be substituted for the chalk or lime-water. If these simple proceedings are not sufficient to restore the infant's health, it will be wise to seek at once for another source of milk supply, and to place the suspected milk in the hands of the medical officer of health or of the public analyst, in order that it may be submitted to a thorough chemical and microscopical examination. The difficulty sometimes found in obtaining an unvaryingly good milk supply, as well as practical convenience in many respects, has led to the extensive employment of various forms of condensed milk. They form undoubtedly the best substitute for fresh cows' milk which we possess, and are a great boon especially to the poor in large towns where the milk supply is often scanty, not always fresh, and sometimes of bad quality. I should certainly prefer condensed milk for an infant to milk from cows living in close dirty stables, such as my experience thirty years ago made me familiar with in some parts of London.