496 



THE POPULAR SCIENCE MONTHLY. 



ratory experiments : and certainly in this 

 respect America has little to fear from im- 

 portations of " crumbs." The laboratories 

 of the Stevens Institute of Technology, of 

 the Lawrence Scientific School, of Columbia 

 College, of the University of New York, and 

 others, bear faithful witness to thorough 

 work, and to real advances in the most 

 deUcate researches of physics. It must be 

 remembered, too, that great works of anal- 

 ysis are not plenty in any country, and we 

 think that the masterly works of Ferrel, on 

 the theory of the tides, redeem America 

 from reproach for 1874 at least. 



The " Report of the Committee on the 

 Preservation of Forests" follows, and from 

 it we learn that this important subject is 

 now before Congress in a proper form, and 

 that we may reasonably hope for some 

 action from that body. 



The Association is divided into two sec- 

 tions, A and B, the first of " Mathematics, 

 Physics, and Chemistry," the second of 

 " Natural History," and we can judge of the 

 attention given to the various subjects by 

 noting the number of papers devoted to 

 each. 



Thus we find for Mathematics, one ; for 

 Astronomy, three ; for Ph'/sics, eight ; for 

 Chemistri/, eight; for Slatistics, one. This 

 completes the work of Section A. In the 

 section of " Natural History " we find for 

 Geology, eleven papers ; for Paleontology, 

 one ; for Botany, four ; for Zoology, twelve ; 

 for Anthropology, two. 



It cannot fail to be noted that on the 

 whole this volume of 378 pages is a decided 

 improvement on its predecessor of 669 pages, 

 particularly in the character of the publi- 

 cations printed. The printing committees 

 seem to have exercised a careful scrutiny 

 of the work put before them, and their se- 

 lection has made the volume not uncredit- 

 able to American science. 



We had not intended to notice in detail 

 any of the separate papers, since they are 

 all to be seen in the volume itself, and since 

 very full reports of them were published by 

 the New York Tribune during the time of 

 the meeting ; but it is impossible to avoid 

 calling attention to a paragraph in a paper 

 by Dr. Asa Gray, the great botanist of Cam- 

 bridge, on the growth of the trunks of 

 trees. The question was raised as to whether 



a tree in growing expanded its main trunk 

 vertically in those parts once formed; ex- 

 periments were made to determine this 

 point by Dr. Gray, and the experiments and 

 theories of various correspondents are ana- 

 lyzed by him. Of one he says : 



[This] correspondent, "who has read in the 

 older books on the structural botany a good 

 deal more than there is any foundation for, 

 about a collum, or collar, between the root 

 and the stem, and who states that the wood 

 is here of horizontal instead of vertical fibres, 

 or cells, suggests that the trunks lengthen 

 at their base only, and by the increase of 

 these horizontal wood-fibres, formed one 

 above the other, at the level of the ground. 

 Now, in the first place, this supposed collar 

 was only between the primary root and stem 

 of a seedling ; so that only trees raised from 

 seed could be lengthened by its growth, not 

 those originated from suckers, layers, or 

 cuttings. Next, trunks lengthened in this 

 way would come to have the butt-log com- 

 posed of wood with horizontal fibres, which 

 I think nobody ever saw. And, finally, there 

 is no such collar, even in the seedling, with 

 horizontal fibi-e, interposed between the root 

 and stem." 



We quote this to show that in some in- 

 stances botany is more than an exact science 

 it is a precise one. 



The Maintenance of Health. By J. Mil- 

 ker FoTHERGiLL, M. D. 366 pages. 

 New York: G. P. Putnam's Sons, 1875. 

 Price, $2.00. 



This book is, in the author's first and 

 last words, " a medical work for lay read- 

 ers," " writ out of great good-will unto my 

 countrymen." The book is divided into 

 thirteen chapters, with the salient points 

 summed up at the end of each in a list of 

 propositions. The first chapter treats of 

 health, wliat it is, and how maintained 

 laying down many propositions, among 

 which are that there are difierent types of 

 health, and tliat bodily and mental health 

 must go hand-in-hand. The next three 

 chapters treat successively of health in 

 youth, or the period of growth ; health in 

 adult life ; and health in old age, or the pe- 

 riod of decay. Chapter V. discusses the 

 quality, quantity, and properties of food 

 and clothes. Chapter VI. is given to stim- 

 ulants and tobacco, in which the author 

 uses these propositions : " Alcohol is a re- 



