August 29, 1901] 



NATURE 



421 



gisticated air," and he endeavoured to explain all his 

 own results as well as the changes occurring in combustion 

 and respiration on the same theory. Thus although in 

 1774 he prepared oxygen he did not discover it in the true 

 sense of the word, because he failed to understand his 

 discovery. This was reserved for Lavoisier, who, in the 

 year following (i775). published his paper "On the 

 nature of the principle which combines with metals 

 during their calcination," in which he conclusively 

 showed that the principle is taken up from the air, is 

 part of the air. Two years later he demonstrated that 

 the same substance " is the constructive principle of 

 acidity," and he called it the acidifying (or oxygine) 

 principle. 



The composition of the atmosphere now became clear ; 

 the discovery, or rediscovery, of nitrogen (or azote, from 

 its inability to support life) naturally followed, and the 

 gaseous exchanges in the lungs between o.xygen from the 

 air and Black's "fixed air," or " aeriform calcic acid," as 

 it was at first termed by Lavoisier, were demonstrated, 

 as we at present understand them. " Thus at a single 

 stroke did this clear-sighted inquirer solve the problem of 

 oxidation, and almost, if not quite, the problem of respira- 

 tion." This was in 1777. 



Three years later Lavoisier and Laplace published their 

 celebrated memoir on heat. In this they definitely state 

 —as the result of measurements of the amount of heat 

 produced by the combustion of a given weight of carbon 

 when burned to carbonic acid, and the amount given out 

 by an animal with the production of a given quantity of 

 carbonic acid— that " respiration is a combustion, slow it 

 is true, but otherwise perfectly similar to the combustion 

 of charcoal. It takes place in the interior of the lung 

 . . . The heat developed by this combustion is com- 

 municated to the blood . . . and is distributed over the 

 whole animal system." Later Lavoisier recognised that 

 the combustion of hydrogen, which had been discovered 

 by Cavendish in 17S1, takes a part in the production of 

 animal heat. Not until long after Lavoisier— not, in 

 fact, until well into the nineteenth century— was it recog- 

 nised that the combination of oxygen with carbon and 

 hydrogen occurs, not in the lungs, but in the tissues. 

 Lavoisier was but fifty years old when he was swept 

 away, in 1794, in the maelstrom of the Revolution ; all too 

 soon for the science which he had done so much, and in 

 so short a time, to advance. 



The tenth and final lecture is devoted to the older 

 doctrines of the nervous system. The views of \'esalius 

 and of Descartes (i 596-1650), of Willis (1621-1675) and 

 Glisson (i 597-1677), of Borelli, of Stensen (1638-1686) 

 and of Haller (1708-1777) are here set forth, and the 

 history of the doctrine of " irritability " of tissues, first 

 enunciated by Glisson and afterwards by Haller, is 

 described. But, as a matter of fact, the physiology of 

 the nervous system is almost entirely the product of the 

 nineteenth century ; before that it can scarcely be said 

 to have a history ; everything was obscure, and the place 

 of facts was occupied for the most part by vague 

 speculations. 



One of the most prolific subjects of such speculation was 



the seat of the soul, which was assigned by van Helmont 



(as we have already seen) to the pit of the stomach, by 



Descartes to the pineal gland, by Haller, with better reason, 



NO. I 66 I, VOL. 64] 



to the medulla oblongata. " But we have learned much 

 since Haller's time." . . . "And if he," adds Foster, 

 "with the knowledge and the means at his command, 

 seems to us to-day to have often gone astray, shall not we 

 ourselves one hundred years hence still more often appear 

 to have gone astray ? " To which it may perhaps be 

 replied that, although it will always be human to err, yet 

 the means at our command are so much more complete 

 and the methods so much more accurate that it is far 

 less likely that we shall take a start in a wrong direction, 

 or, having taken it, shall continue in it ; in this at least 

 we have an advantage over our eighteenth century pre- 

 decessors, whose methods were, comparatively speaking, 

 rough and their means and opportunities relatively 

 limited. 



Whilst endeavouring in the above account to give a 

 general idea of the character of the book with which 

 Sir Michael Foster has enriched the world of science, it 

 is by no means an easy task to do adequate justice to 

 the mine of literary and historic research which the author 

 has laid open to view. But if a perusal of this account 

 serves to induce others to go to the original, we can 

 promise them that they will find it as interesting a story 

 as may be met with for many a long day. And it is to 

 be hoped that the perusal of Sir Michael Foster's history 

 will stimulate the desire of its readers to make the direct 

 acquaintance of the great authors who, during the three 

 centuries under review, laid the foundations of modern 

 physiology and, with it, of the sciences upon which 

 modern physiology is based. E. A. S. 



FILTRATION OF WATER. 

 Water Filtration Works. By James H. Fuertes. Pp. 

 xviii -h 283. (New York :' John Wiley and Sons ; 

 London : Chapman and Hall, Ltd., 1901.) Price 

 los. bd. 



FILTRATION, which is generally regarded as an 

 essential process in the provision of domestic 

 water-supplies for large towns in England, especially 

 when rivers constitute the source of supply, has been 

 neglected to a considerable extent in the United States, 

 and, therefore, the publication of a book, by an American 

 engineer, dealing wholly with this subject, will be par- 

 ticularly valuable if it should lead municipalities in the 

 United States to the more general adoption of this safe- 

 guard against the distribution of water to large popu- 

 lations in a condition dangerous to health. Polluted 

 river waters, in their natural condition, have proved very 

 fatal to our troops in South Africa, as shown by the high 

 rate of mortality from enteric or typhoid fever ; and 

 the author, at the commencement of his book, draws a 

 very striking contrast between the annual death-rate 

 from typhoid fever per 100,000 persons in cities supplied 

 with pure or filtered water, such as the Hague, Munich, 

 Dresden, and Berlin, with a typhoid death-rate of only 

 from 47 to 7, and Washington, Louisville, and Pitts- 

 burg, supplied with unfiltered river water, where the 

 yearly typhoid death-rate for several years has averaged 

 71, 74, and 84, respectively, per hundred thousand of 

 population. River waters are to some extent purified by 

 natural agencies during their downward flow if no fresh 

 causes of contamination are introduced, depending on 



