An Elementary System of Physiology

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1836. Excerpt: ... CAUSES OF DISSOLUTION. 823 commune, and the perceptions which they excite there are less vivid. The state of the intellectual facidties undergoes, at the same time, a gradual progress, which bears a relation to these alterations in the physical powers. In infancy the brain seems principally adapted to receive those impressions which are connected with the contractile functions. During childhood the mental powers gradually unfold themselves, and the different faculties rise up in succession, according to the operation of external objects, modified by the peculiar organization and innate propensities of the individual. In youth the impressions upon the senses are the most vivid, there is a greater rapidity of conception, and from this cause there is a greater tendency to form powerful associations. This, therefore, is the season of fancy and imagination, while the power which the mind possesses of associating its ideas with facility gives strength to the memory, and enables us to retain the knowledge which is acquired. As age advances, impressions on the organs of sense produce less effect, new associations are less easily acquired, and in general the mental faculties have more difficulty in undergoing any kind of alteration. While former habits are retained with greater force, and while old associations are recollected with peculiar correctness, recent events are forgotten, and new modes of life are with difficulty had recourse to. At length the powers of the system entirely fail; the external senses become callous to the impression of surrounding objects, and the mental faculties become irregular and uncertain in their operation. Although the decay of the physical and of the intellectual powers does not always proceed with equal rapidity, yet the respite ...