NA rURE 



[May 



1 90 1 



percentage of corpuscles than the normal can be at once 

 arrived at with considerable accuracy by determining at 

 what dilution the flame of a candle can be seen through 

 the mixture. By 'the employment of this method Dr. 

 Oliver has made many determinations of the percentage 

 (as compared with normal) of corpuscles in blood taken 

 under different conditions both in health and disease, 

 the chief of these varying conditions being those relating 

 to time of day, rest and exercise, digestion, temperature 

 and altitude. It is known that the number of red 

 corpuscles per cubic millimetre may rise from 4,500,000 

 at sea-level to 7,000,000 or 8,000,000 at elevations of from 

 6000 to 14,000 feet above sea-level. This has been 

 determined by \'iault on the Cordilleras and by Egger 

 and others on the Alps, and is confirmed by the author, 

 who finds that the increase is apparent within 24 hours 

 and attains its maximum within the first week. It is, 

 however, not as great as had been supposed ; part of the 

 former results depending upon an inaccuracy (at low 

 barometric pressures) in the instrument usually employed 

 for enumeration, an inaccuracy not shared by the cyto- 

 meter employed in these investigations. The description 

 of these two methods and their results occupies nearly 

 one half of the book, the other half being taken up by a 

 description of methods for investigating the condition of 

 the bloodvessels. 



Of these the first is one for determining the average 

 blood-pressure in the arteries. It is based upon the 

 ascertained fact that any instrument vi-hich is used to 

 observe the arterial pulse by external application gives 

 the largest indications of pressure variations when the 

 force with which it is itself pressing upon the artery is 

 equivalent to the average blood-pressure within the 

 vessel. This principle has already been employed for 

 gauging the blood-pressure in man by Mosso and others, 

 but the instrument which has been contrived by Dr. 

 Oliver for the purpose, and which he called a " hsmo- 

 dynamometer," is both more sensitive and more easy of 

 application than most others which have been devised, 

 the pressure being applied to a sprmg through an india- 

 rubber bag or pad filled with fluid, and the indications 

 being directly read off upon a dial (as in Hill and 

 Barnard's original sphygmoscope). An even more in- 

 genious instrument is the " arteriometer,'' which directly 

 and with great accuracy measures the calibre of an artery, 

 such as the radial, through all the tissues which cover it. 

 Dr. Oliver has, with the aid of these instruments, recorded 

 a very large number of observations upon the effects upon 

 blood-pressure and upon the arteries of varying physio- 

 logical conditions such as posture, exercise, emotions, 

 rest and sleep, fatigue, food and digestion, temperature 

 and climate ; for the details of these and for many other 

 observations on the effects upon the circulatory system of 

 baths, massage and various other forms of treatment the 

 interested reader is referred to the account which the 

 author has himself given. The book furnishes an excellent 

 illustration of what can be done by the scientific physician 

 for the advancement of physiological knowledge, and its 

 perusal will repay, not only the clinician for whom it is 

 primarily intended, but also the physiologist who desires to 

 compare the results which he obtains by experiments upon 

 animals with those which can be obtained by experiments 

 upon man. E. A. S. 



NO. 1644, VOL. 64] 



A GERMAN NATURALIST IN THE WE SI 



INDIES AND AMERICA. 



Von den Antillen zum Fernen Westen; Reiseskizzen 



fines Naturforschers. By F. Doflein. Pp. iv 4- 180. 



Illustrated. (Jena : G. Fischer, 1900.) Price M. 6.50. 



Al/HILE containing little or nothing in the way O/ 



^ * absolute novelty, this narrative of the travels of 

 a German naturalist in the West Indies, Mexico, Cali- 

 fornia, and the far Xorth-West of America is a pleasantly 

 written and charmingly illustrated volume which car» 

 scarcely fail to interest and attract a large number of 

 his fellow-countrymen. According to the author, German 

 travellers but seldom visit the countries through which he 

 passed, so that the greater part of what he has to tell 

 will be new to the majority of his readers. With the 

 exception of two, the originals of the photographic 

 illustrations, which add so much to the attractiveness of 

 the volume, were taken by the author himself ; and the 

 exquisite manner in which these photographs have been 

 reproduced reflects the highest credit on the firm to whom 

 the task was entrusted. 



The first part of the book, which is divided into seven 

 chapters, is devoted to the West Indies, where Martinique 

 was the first island visited. Here the author was much 

 interested in the botanical gardens, where he was 

 struck by the richness of the vegetation, and especially 

 by the luxuriance of the lianas. Several charming views 

 in the island are given. 



The author's next point was Barbadoes, where he left 

 the great ocean steamer to take passage in a smaller 

 vessel for a cruise among the lovely isles of the Lesser 

 Antilles group. After devoting several chapters to his 

 experiences among these, the narrator discusses m the 

 sixth the racial problems presented by the West Indies, 

 illustrating a few characteristic types. In Chapter vii. 

 he treats of the fauna of the Lesser Antilles, dwelling 

 on the close connection existing between the animals of 

 that group and those of Venezuela, Colombia and Central 

 America, and giving good pictures of a few of the more 

 remarkable forms, among them the dreaded y^r-n'^-/««f^ 

 snake. A section of this chapter describes in some 

 detail the coast fauna of Martinique, a striking feature 

 of this part being the photograph of a tropic-bird in 

 flight. 



The remaining nine chapters, forming the second half 

 of the volume, describe the continental portion of the 

 author's tour, and are at least as full of interest as their 

 predecessors. In the first of these chapters (viii.) we 

 have an instructive sketch of the ancient buildings and 

 weapons of Mexico, which the author calls the Pompeii 

 of America. In addition to a view of the celebrated temple 

 of the sun and photographs of stone weapons, the author 

 gives a plate of human and animal clay masks collected 

 by himself at Teotihuacan. In Chapter ix. we have a 

 description of a traverse of the great desert tract of 

 Mexico, illustrated by an excellent photograph of giant 

 cactuses ; while, in striking contrast to this, the reader, in 

 Chapter x., is introduced to the glories of a summer's day 

 in California. Following the latter is a description of a 

 Chinese settlement in the same country, where the 

 photograph of "Chinatown" will not fail to impress the 

 reader with the importance assumed by the Mongolian 



