It is therefore of great importance to be able to read aright the instructions of Nature, and to act in conformity with their meaning. In practical benefit to ourselves it will make a great difference whether we regard indigestion as merely an accidental and capricious occurrence unconnected with conduct, or as purposely meant to warn us from continuing to act against laws instituted to secure our wellbeing and happiness. In the former case, we may go on unsuspectingly in the road to destruction till it is no longer in our power to turn back; whereas, in the latter, we cannot feel a single pang of indignation without being reminded of some aberration from the path of duty, and seeking to return by the shortest way. It is too true that, even when aware that we are going wrong, we do not always choose to retrace our steps; but it is not less true, that we shall be more likely to fulfil the laws of Nature when we are made acquainted with their existence and intention, than when left to the guidance of ignorance alone. It must be observed also, that hitherto mankind have not been taught the requisite knowledge till after their habits of action were formed; and therefore no inference can be drawn from their conduct in circumstances so unpropitious, which can, with any fairness, be held as applicable to the time when knowledge shall be communicated to the young as an indispensable part of a useful education. If over-feeding be the prevailing error among the middle and higher classes of the community, the opposite condition is as unquestionably that of a large proportion of the labouring poor. Pressed upon all sides by the powerful competition both of constantly improving machinery and of a superabundant population, the manual labourer is impelled to undergo an amount of ever-recurring bodily exertion which far exceeds the natural powers of his constitution, even when supported by the fullest supply of nourishment; and when, as often happens along with this excess of labour, his food, from inadequate wages, the size of his family, or his own injudicious management, is defective in quantity or in quality, the consequences to his health and happiness are disastrous in the highest degree.