Symmons's zeal for Milton has induced him not merely to vindicate the poet from his principal enemies, Dr. Johnson and Mr. Thomas Warton, but to give them in return a Rowland for their Oliver. ART. XII. An Essay on Respiration. Part First and Second. By John Bostock, M.D. 8vo. pp. 275. 68. Boards. Longman and Co. Mo-y. No part of Physiology has undergone a more complete revolution within these few years, than the doctrines which relate to Respiration. From the discoveries of chemistry, which have thrown so much lustre on the Philosophy of the present day, nearly all the knowlege which we possess concerning this function is derived; and instead of the vague and limited uses formerly ascribed to it, we now find that through its means some of the most important changes are effected in the animal economy, and that it is intimately connected with several processes of the first consequence to health and life. We are happy, therefore, to notice, in the present work, a general and very correct and perspicous view of the present state of our knowlege on this subject. We regard the detailed examination of one particular function as the most likely mode of elucidating it; and while we give the author credit for the industry and judgment which he has exercised in this essay, we would express our hopes that he will carry on the plan which he has proposed to himself, of extending his views to the Pathology of respiration, to the different affections in the various natural situations in which the body is placed, and to the connection which exists between this and other functions. The field is ample and interesting, and we have no doubt of Dr. Bostock's abilities for cultivating it. An account of the process of Respiration occupies the first part of this volume, and it is preceded by a description of the human organs destined for this purpose, with their mechanism. The author then extends his inquiry to a critical examination of the different accounts which have been given by various Physiologists of the bulk of a single inspiration, and the capacity of the thorax in its different states of distension. He considers the experiments of Drs. Goodwyn and Menzies as the most successful on these points; and he agrees with the latter in thinking that about 40 cubic inches are discharged at an ordinary, and with the former, that about 109 cubic inches are left in the lungs after a complete expiration. Dr. Menzies supposes that about 70 cubic inches can be discharged from the lungs after an ordinary expiration; and therefore by adding 109 to 70, he concludes that 179 cubic inches are the capacity of the lungs after an ordinary expiration, and that 179 added to 40 (the bulk of an ordinary expiration,) give 219 as the capacity of the lungs after an ordinary inspiration. Dr. Bostock is of opinion that nearly double the quantity which Dr. Menzies supposes, or about 131 instead of 70 cubic inches, can be discharged by a powerful effort, after an ordinary expiration; and that therefore 280 cubic inches form the capacity of the lungs in their natural state of inspiration. From these data, he estimates that by each ordinary expiration part of the whole contents of the lungs is discharged, and that by the most violent expiration, somewhat more than of the air contained in them is evacuated. Supposing that each respiration occupies about 3 seconds, a bulk of air nearly equal to three times the whole contents of the lungs will be expelled in a minute, or about 4114 times their bulk in 24 hours. The quantity of air respired, during the diurnal period, will be 1,152,000 cubic inches, or 665 cubic feet. With regard to the cause of the first inspiration, the author supposes, with considerable appearance of truth, that when the position of the animal is changed (as it must be) after birth, a considerable pressure is taken off from the thorax and abdomen, the elasticity of the cartilages raises the ribs, and the abdominal viscera descend; by all which means, the capacity of the lungs is enlarged; and the air rushes in spontaneously to supply the void. He thinks that the alternation of inspiration and expiration depends on a certain power which the blood acquires, when it has remained some time in the pulmonary. vessels without the access of fresh air, of stimulating the diaphragm, and thus making room, by its contraction, for the external air to rush in; while, on the other hand, when the. blood has undergone the necessary change, and the state which caused the contraction of the diaphragm no longer exists, this muscle relaxes, and expiration ensues. This opinion appears to us to be rather hypothetical; and we do not perceive that much is gained by laying aside, in reasoning on this subject, the consideration that respiration is a function under the influence of the will. It is true that, in ordinary circumstances, we are insensible to any uneasy sensation in the means of continuing respiration, and therefore are not intitled to infer that the cause of the alternation of respiration is to avoid such unpleasant feeling: but at the same time it may be remarked, that the limits of ordinary respiration are closely contiguous to those of uneasy sensation; and that from the number of instances of associated motions, which take place before consciousness exists, we cannot altogether set aside the idea that nature has 十 wisely wisely guarded us against the interruptions of a function necessary to existence, by making the personal feelings of the individual interested in its continuance. Part II. of this essay treats of the direct effects of respiration; which the author divides into the mechanical effects caused by the dilatation and contraction of the thorax, the change produced on the inspired air, and the alteration effected in the blood itself in its passage through the lungs. With regard to the first point, he is of opinion that, in the usual act of respiration, the blood is transmitted through the lungs with nearly equal facility; and that it is only in extreme cases that the retardation, imagined by many authors to exist, can be supposed to take place. He also thinks that the other effects of respiration on the vascular and lymphatic system have been. much over-rated.-The two remaining subjects of discussion relate to the changes which are effected on air that has been inspired, and on the blood which has passed through the lungs. Dr. B.'s summary of the state of our knowlege on the first particular we shall give in his own words: 1. A quantity of oxygene is consumed in respiration; in ordinary circumstances atmospheric air, which has been once respired, loses nearly 04 of its bulk of oxygene; in 24 hours a man consumes a quantity which will weigh about 2lbs. 8oz.; somewhat more than 26 cubic feet. 2. A quantity of carbonic acid is generated by respiration; its volume is less than that of the oxygene absorbed, nearly in the proportion of 37 to 45; the weight of carbonic acid formed in 24 hours is about 3lb.; a volume of about 22 cubic feet. 3. The whole volume of the air is diminished by respiration; the degree of diminution is not very accurately ascertained, but it may be estimated at about of its bulk. 4. A quantity of aqueous vapour, the amount of which is still undetermined, is emitted from the lungs. 5. It is probable that a small portion of azote is absorbed, upon an average about part of the air respired, making in 24 hours about 4oz or 4 cubic feet. T 6. From the ascertained proportion in which the oxygene and pure charcoal exist in carbonic acid, it appears that a greater quantity of oxygene is consumed, than is necessary for the formation of the carbonic acid which is produced.' It is necessarily very difficult to discover the changes which the blood undergoes in its passage through the lungs.-Dr. B. has, however, given a comprehensive view of what has been ascertained or rendered probable on this subject; and of the general inferences we shall make an abstract. The blood, in its passage through the lungs, emits carbonic acid gas and absorbs oxygen, and is thus converted from a dull REV. JAN. 1807. G purple purple to a bright scarlet colour. Dr. B. also thinks that probably a small quantity of azote is absorbed by it. The oxygen is at first loosely combined with the mass of blood, but, during the circulation, it enters into combination with its carbon, and forms with it an oxyd; which, when it is brought back to the lungs, unites with an additional quantity of oxygen, so as to form carbonic acid gas, which is removed by the act of expiration. The capacity of arterial blood for heat is also increased. The concluding chapter comprehends a general account of the experiments which have been made on the respiration of gases by various philosophers; and a large appendix contains several interesting illustrations and discussions, which could not so properly enter into the body of the essay. We are sorry that our account of this work has been delayed by accidental circumstances, of a private nature: but the terms in which we now mention it, and the general opinion entertained of its merits, forbid any suspicion that we could willingly treat it with disrespectful neglect. Yell. ART. XIII. A brief Examination into the Increase of the Revenue, TH with a distinctness and a precision that are unparalleled: yet he disdained the counsels that were thus offered to him, and occasioned the author of them to be regarded as the enemy of his country. This is a grievous aggravation of his errors: but his errors were grand like himself, and under their fatal conse quences his elevated soul fell a victim, in lamentable expiation of them. On his traduced opponent, his desponding country was then glad to throw herself; and to him she looked for her deliverance, when brought to her lowest state. Let, then, the panegyrists of the late Premier confine their praises to his oratory, to his financial abilities, to his unsullied integrity, and to his high honor: on the topic of the external relations of the country, if they are wise they will be silent. In the new part of this pamphlet, (the largest portion of which was published in two tracts, in the years 1792 and 1799*) Mr. Rose observes: To an upright minister in Great Britain, zealous for the interest and honor of his country, there is no reward of profit, emolument, or patronage, which can be esteemed a compensation for the labours, the privations, the anxieties, or the dangers of his situation it is in the approbation of his sovereign, and in the suffrage of his countrymen, added to his own conviction of having done every thing to deserve it, that he must look for that reward which is to console him for all the cares and troubles of his station; the opposition of rivals; the misrepresentation of enemies; the desertion or peevishness of friends; and sometimes the mistaken censures of the people. "Tis the honourable ambition that looks beyond the present time that must create, encourage, and support a virtuous and enlightened statesman;-that must confer on his mind the uprightness and purity that rise above all self-advantage; the courage that guards the state from foreign hostility or internal faction; the firmness that must often resist the wishes, to ensure the safety, of the people. This is the legitimate ambition of a statesman; and that Mr. Pitt possessed it, his friends are convinced; but he has been some. times accused (by those who, although their opposition was active and systematic, yet knew how to honour the man) of a less laudable and less patriotic ambition, that wished "to reign alone," to exclude from the participation of office and of power other men, whose counsels might have assisted him to guide the country amidst its difficulties and embarrassments, or might have contributed to its safety in the hour of its danger. It is however perfectly well known to some of the highest characters in the kingdom, that Mr. Pitt, after the resignation of Mr. Addington, in the summer of 1804, was most anxiously desirous that Lord Grenville and Mr. Fox should form a part of the new administration, and pressed their admission into office in that quarter where only such earnestness could be effectual; conceiving the forming a strong government as important * See Rev. Vol. xxviii. N. S. p. 471. |