Independent of accidental maladies which happen at every age, but become more dangerous and more frequent at the latter periods of life, all men are subject to natural infirmities, that originate solely from a decay of the different parts of the body. The muscular powers lose their firmness, the head shakes, the hands tremble, the legs totter, and the sensibility of the nerves decreasing, every sense becomes blunted. But the most striking infirmity is, that men very aged, are unequal to the office of generation. Of this inability two causes may be assigned, a defect of tension in the external organs, and a decay of the seminal fluid.[B] The latter defect, however, may be supplied by a young woman; and thus it is that we sometimes see men at an advanced period of life become fathers, but then they have a much less share in their children than young ones; and thence it happens, that young persons, when married to old men, decrepid and deformed, often bring forth monsters, and children more defective still than their fathers. [B] Our author here enters into a repetition of the nature of the organic animalcules, and to account for the defect of tension in the external organs, but which we have passed over, not doubting our readers would feel the propriety of his concluding remark, that this was an improper place for such discussions. The scurvy, dropsy, and such diseases as proceed from a vitiated state of the blood and other fluids, are the most fatal to mankind; but these fluids depend upon the solids, which are the real organic parts. As we become advanced in life the vessels contract, the muscles lose their strength, and the secretory organs are obstructed; from which causes the blood, and other fluids, become viscid, and occasion those diseases which are generally supposed to arise from vitiated humours. The natural decay of the solids are, therefore, the original causes of those disorders; nevertheless, if the fluids become stagnated, or are obstructed in their circulation, by a contraction of the vessels, they produce alarming symptoms, and soon corrupt and corrode the weakest parts of the solids. Thus do the causes of dissolution continually multiply until they put a period to our existence.