AGE. 



once distinguished it from the dust, and that 

 not less literally than truly it has become more 

 and more " of the earth earthy." 



We have now traversed as far and as mi- 

 nutely as our space would allow, the organs 

 and tissues, with their various alterations. It 

 remains for us to inquire whether any one of 

 them may be considered to stand in the rela- 

 tion of cause to the others. We have already 

 dismissed the supposition, that rigidity and con- 

 cretion are productive of the other alterations, 

 and we also partly entertained the question, 

 when treating of the relations between assimi- 

 lation, the fluids, and the organs subservient to 

 circulation and digestion. But there are one or 

 two additional points which must be alluded to 

 in this place. 



The decay of all the organs, concerned in 



the life of relations, has been shewn to depend 

 on a failure in the actions which are necessary 

 to their generation and maintenance ; these 

 organs may, therefore, be dismissed at once 

 from our inquiry into the causation or priority 

 of the processes of degeneration. Yet the 

 observation of the marked declension of the 

 function of the nervous system throughout the 

 body, has led to the hypothesis, that the 

 failure in this power is the ultimate fact in the 

 history of our decline, the fact to which all the 

 others maybe traced. This view is suggested 

 by Dr. Roget in his justly-admired article on 

 Age, in the Cyclopaedia of Practical Medicine. 

 He considers the general condensation of tissue 

 throughout the system, to be occasioned by a 

 diminished force of circulation, which allows 

 the capillaries to collapse and become obli- 

 terated ; the weakened circulation this distin- 

 guished author is inclined to attribute to a 

 diminution of nervous power in the muscular 

 fibres of the heart ; whence he infers that the 

 declension of nervous power bears the priority 

 in the chain of events. W T e do not fee! pre- 

 pared to adopt the inference ; for if we admit 

 this failure in the innervation of the heart, (and 

 whether its fibres are dependent on nerves for 

 their contractility, is still an unsettled ques- 

 tion,) are we to pass over the condition of the 

 blood ? Might we not say that the enfeebled 

 contractions of the heart are referable to an 

 alteration in the properties of its appropriate 

 stimulus ? It is known that this vital fluid has 

 been less affected by respiration than in former 

 periods of our existence ; we might therefore, 

 when searching for the earliest antecedent in 

 decay, stop at the imperfect arterialization of 

 the blood. But this would be, in our humble 

 opinion, to pause too soon. The deficient 

 oxygenationof the circulating fluid is sufficiently 

 well known to be the effect of certain changes 

 in the apparatus of respiration. And to what 

 do these changes belong 1 To a variety of 

 structural, functional, and nervous phenomena, 

 which, if pursued, would lead us into a maze 

 of events, from which it would be impossible 

 to select that which was earliest in its occur- 

 rence. Or if we leave the respiratory system, 

 and follow the blood backward to the process 

 of chylifkation, and ultimately to digestion, we 

 shall, as was shewn above, be equally unsuc- 



cessful in obtaining satisfaction. Or finally, if 

 we return to the heart, and investigate the dimi- 

 nished nervous power, admitting this diminu- 

 tion to be alone sufficient for the debility of 

 circulation, is it possible to stop at this pheno- 

 menon ? Nervous power is nothing but the 

 function of nervous substance, and whether the 

 latter belongs to the ganglionic system, or to 

 the cevebro-spinal, it may have undergone some 

 change, or have been stimulated differently 

 from usual. We know that the sensibility of 

 the nervous system is most intimately connected 

 with thequalityof the blood, and with the force of 

 its impulse ; so that if it be true that diminished 

 circulation is the effect of diminished innerva- 

 tion, it is no less true that the latter is also the 

 result of the former. Thus it appears that in 

 this inquiry we are constantly arguing in a 

 circle, and it can scarcely be otherwise ; the 

 principal structures and functions of the organic 

 life commenced simultaneously ; they must,de- 

 cline simultaneously : they assisted one another 

 to grow ; they accelerate each other in the way 

 to dissolution. If, however, we are disposed 

 in some measure to qualify this remark, and 

 still hold that there must be some organic 

 changes primary in the work of decay, all ana- 

 logies must, we think, conduct us to the simple 



processes of assimilation and secretion, into 

 which all the more complicated functions must 

 be ultimately resolved ; but we can go no 

 farther, for we know not what determines or 

 modifies the play of those subtle affinities, 

 motions, and contractions, in which such 

 changes consist. 



Some fancy that the enigma is solved by the 

 hypothesis of a diminished vital power; but 

 we have already attempted to show that the 

 interpretation is without value, when applied to 

 the cessation of development; the same reasons 

 render it equally useless as a key to the hiero- 

 glyphics of decay. Not less vain were the 

 endeavours of those who could satisfy their 

 philosophy with such a subterfuge of ignorance 

 as was afforded in the theory of a sum of exci- 

 tability, originally allotted to the system, and 

 gradually exhausted, &c. ; as if excitability 

 could possibly mean any thing more than an 

 expression of the collective phenomena of ex- 

 citement, or vital movement. It is exactly on 

 a par with the doctrine of decreasing vitality.* 

 Some talk prettily and poetically of the vital 

 flame burning out, of oil gradually wasting, of 

 fuel expended, phrases applicable enough as 

 metaphors, but absurd when propounded, as 

 they too often are, as statements of matters 

 of fact. 



When philosophy has failed to discover an- 

 tecedences, she may still find a prolific source 

 of employment in the study of harmonies. 

 There is no event to be found in the relation of 

 cause to those organic changes which, without 

 the intervention of accidental agents, ultimately 

 affix a bound to the duration of man's existence. 

 As no cause can be elicited for the termination 

 of development, neither can we better explain 



ccssc 



'La gene dc 

 " Ciibanis. 



1'influence vitulc s'accroit sans 



