207. There exists a great variety in the qualities of the food which is furnished by this class of animals, with regard to nourishment, stimulus, and digestibility: the whiter meat of domesticated birds, as the wings and breasts of chickens, contains less nutriment, and is less digestible, than that which is furnished by wild birds, as the partridge, etc.; but the former is, at the same time, less stimulant and heating than the latter. These are the circumstances which are to direct the medical practitioner in his opinion. No general rule for the choice of either species can be established: it must be determined by the particular condition of the patient, and the effect which the aliment is intended to produce. The same observation will apply to the flesh of quadrupeds; that which is dark-coloured and contains a large proportion of fibrin, as venison, etc, is easily disposed of by the stomach, and a large quantity of highly-stimulating chyle is produced from it. The whiter meats are, on the contrary, detained longer in the stomach, and furnish a less stimulant chyle.

The former, therefore, will be more easily digested by weak persons, while the latter will frequently run into a state of acetous fermentation; but they may, nevertheless, be preferable on many occasions, inasmuch as they impart less stimulus to the general system. We see, therefore, the folly into which many popular writers have fallen, of stating such or such an article as being wholesome or otherwise; the wholesomeness of an aliment must depend upon its fitness to produce the particular effect which the case in question may require. Van Swieten has justly said, that "to assert a thing to be wholesome, without a knowledge of the condition of the person for whom it is intended, is like a sailor pronouncing the wind to be fair, without knowing to what port the vessel is bound".