78 



AGE. 



so few nutritive actions are transpiring. We 

 have spoken of the altered character of the 

 blood, of its being less arterial and of a darker 

 tint : this change is explained by the alteration 

 in the respiratory system. The lungs are be- 

 come lighter, the cells being relatively much 

 larger,* and the parenchyma, which consists 

 principally of bloodvessels, being greatly di- 

 minished. This alone would not explain why 

 the blood is imperfectly arterialized, because, 

 although the respiratory surface is diminished, 

 less of that fluid enters the organ. But the 

 bronchial membrane is always in a more or less 

 unhealthy condition, being covered with a thick 

 and copious secretion, that constitutes the " old 

 man's catarrh," and prevents a due intercourse 

 between the air and the blood. Besides this 

 circumstance, the expansion of the chest is less 

 perfect in consequence of the diminished elas- 

 ticity of the parietes of the chest produced by 

 the ossification of the cartilages and other 

 causes : the muscles also participate with less 

 energy in the respiratory movements. Every 

 thing in the history of advanced life indicates 

 the diminution in the vigour of the circulation 

 and respiration. The apathy and languor of 

 mind, the deficiency of many secretions, and 

 the general decrease of animal heat, but par- 

 ticularly in the parts most distant from the heart, 

 are all more or less intimately connected with 

 the failure of these vital actions. 



On turning to the digestive apparatus we 

 have abundant marks of deterioration. The 

 teeth fall out, the alveolar processes are ab- 

 sorbed, and the gums become hardened. In 

 addition to these there is a change in the mus- 

 cularity of the stomach; it has become weak, 

 attenuated, and less contractile. The same is 

 true of the intestines. The lacteal vessels are 

 much fewer in number, and scarcely any lym- 

 phatic glands are to be met with. Every thing 

 intimates that the food is less perfectly acted 

 upon, and that consequently less chyle is ex- 

 tracted, and transmitted to the circulation. 



Since, then, in these several systems, we find 

 marks of diminution, impairment, depravation, 

 it is not wonderful that nutrition, which is per- 

 formed by means of the materials supplied by 

 those systems, partakes of the same characters. 

 But as nutritive changes must have occurred in 

 the various deteriorated parts just spoken of, 

 it would be incorrect to say that alterations of 

 tissue depend solely on the alterations of these 



* M. Andral, in his description of the atrophy of 

 the lung which occurs in aged persons, says, " In 

 some cases the walls of the cells disappear alto- 

 gether, and we only find in their stead some delicate 

 lamina or filaments, traversing indifferent directions 

 cavities of various sizes. In the parts of the lung 

 where these alterations exist, there are no longer to 

 be found either bronchial ramifications, or vesicles 

 properly so called, but merely cells of greater or less 

 diameter, divided into several compartments by im- 

 perfect septa or irregular lamina;. Many of these 

 cells bear a perfect resemblance to the lung of the 

 tortoise tribe, and they all approacli to it more or 

 less as to a type of organisation, towards which the 

 human being in this case seems to descend. Pathol. 

 Anat. v. ii. p. 528, translated by Drs. Townsend 

 and West. 



systems, though they are promoted by them ; 

 they must, in fact, have assisted each other. 

 The altered tissues could not have been easily 

 thus changed, without a defect in the quantity 

 or quality of the matters out of which they are 

 formed ; nor could the latter defects have easily 

 occurred without some alteration in the texture 

 of the parts employed in conveying and ela- 

 borating the nutrient fluid. It is an old saying, 

 that the functions of the body form a circle : if 

 this be true of their healthy condition, it is not 

 less so of their diseases and decline. 



The organs and tissues subservient to the 

 organic life having undergone vitiation and 

 diminution, we may expect to find equal or 

 even greater decay in the parts which are alto- 

 gether dependent upon them, or the organs 

 of the supplemental life. These indeed, as 

 they are the last to be developed, are some of 

 the first to present marks of decline, and evi- 

 dently for the same reason, viz. because they 

 are appended to and generated by the other 

 parts of the system, and also are more open to 

 our observation. The body is indeed, in this 

 respect as in many others, not unlike a poli- 

 tical community ; no great change can occur in 

 its internal arrangements, such as a failure 

 or derangement of its energies and resources, 

 without a manifestation of this weakness or 

 disorder in its foreign relations. 



Let us proceed, then, to examine the ravages 

 which are wrought by the hand of time on the 

 organs of locomotion and sensation, in the 

 same order in which we have traced the deve- 

 lopments and amplifications, once lavished by 

 the self-same agent. 



And first of the bones. The process of 

 development in these parts consisted of a 

 certain adjustment of the animal to the earthy 

 matter, in order to give the requisite firmness, 

 toughness, and solidity. As life advances, the 

 phosphate and carbonate of lime are found to 

 exceed the proportion of the cartilage and 

 gelatine. The general conformation of the 

 bones is less regular ; they look shrunken and 

 worn. When handled they feel lighter, not- 

 withstanding the osseous substance is in excess; 

 a fact, which results from the diminished 

 quantity of the fluids, and one or two other 

 circumstances to be mentioned presently. The 

 processes and ridges, once so eminent and dis- 

 tinct, are comparatively effaced ; this alteration 

 accords with the wasting and diminished exer- 

 cise of the muscles that were attached to these 

 eminences. On looking for the lines and spaces, 

 which are occupied in early life by cartilages or 

 membranes, and which are visible even in 

 manhood, we now find every trace of them 

 vanished. Thus, the divisions between the 

 epiphyses and shafts of the long bones, the 

 line of union between the bones of the pelvis, 

 and, in a still more marked degree, the sutural 

 outlines of the bones of the head, are no longer 

 perceptible. They are all filled up with bony 

 deposit, and the pelvis and cranium form 

 single bones ; even the foramina by which the 

 nutrient arteries entered the tissue are con- 

 tracted or obliterated. The cellular structure 

 between the tables of the cranium is removed ; 



