Decembek 1, 1911] 



SCIENCE 



765 



the valuable series of Romanes. Throughout 

 it is conservative, perhaps ultra-conservative 

 in its treatment of such topics as the bio- 

 genetic law, the heritability of modiiications, 

 and some other general subjects. And it is 

 thoroughly orthodox ; the giraffe and the black- 

 smith are not found vsranting. 



The entire American Museum of Natural 

 History vs'ould be required adequately to il- 

 lustrate so inclusive a theme as this. And 

 the complete absence of figures, which were 

 abundantly provided for the lectures them- 

 selves, is a serious defect. The capacity, even 

 of the careful reader, for misunderstanding 

 language, is enormous. Even a few well-se- 

 lected figures would give the reader a fre- 

 quent sense of definite concreteness which is 

 occasionally lacking in some of the passages 

 dealing with the facts of evolution. 



There is no index. 



It is safe to say that this book will prove 

 immensely useful, and its use will not be lim- 

 ited to the unscientific. Students of biology 

 and sociology will find it a valuable aid and 

 summary. In marked and agreeable contrast 

 to Eomanes's work, it is entirely free from con- 

 troversial tone, and its excellent spirit, so well 

 evidenced by the concluding chapters, will go 

 far toward making the doctrine of evolution 

 completely acceptable to those who still per- 

 sist in exempting from evolutionary treat- 

 ment and understanding, certain large and 

 important fields of human action and thought. 

 W. E. Kellicott 



Ouayule, a Rubier Plant of the Ohihuahuan 

 Desert. By E. E. Lloyd. Carnegie Institu- 

 tion of Washington, Publication No. 139. 

 1911. Pp. viii + 213. Plates 46, text fig- 

 ures 20. 



It is seldom that the results of a critical 

 study of one plant from several different view- 

 points are brought together at one time within 

 the covers of a single book. The author of 

 Guayule has, however, collected many facts 

 relating to the growth and utilization of 

 Parthenium argentatum Gray, which are 

 worthy of notice. The interest in the present 

 work from the scientific standpoint is en- 



hanced by the fact that the subject of the in- 

 vestigations is a native of desert regions rela- 

 tively little known botanically or ecologically. 

 Erom the economic standpoint it is of interest 

 as furnishing a record of a plant of peculiar 

 importance commercially, whose life history 

 and habits were hitherto practically unknown, 

 though subjects of abundant speculation and 

 conjecture. 



The first chapter presents a brief historical 

 account of the Guayule and its use. The 

 writer traces the development of the industry 

 and describes some of the methods of extrac- 

 tion, which in this case are based upon the 

 fact that the rubber is not produced in latex 

 which issues from incisions in the bark, but is 

 obtained only upon trituration of the stem, 

 branches and roots of the plant. Involving, 

 as it does, the immediate destruction of the 

 whole plant, the manufacture of Guayule rub- 

 ber is attended by the prospect of an early 

 depletion of the natural supply. Hence in- 

 vestigations were begun looking to the 

 placing of the enterprise upon a permanent 

 footing. 



The environment of Guayule and its biotic 

 relations are discussed in the second chapter. 

 Parthenium argentatum is distributed widely 

 over the Mexican plateau and on hills whose 

 soil is chiefly of limestone origin. Its alti- 

 tudinal distribution is from 2,000 to 10,000 

 feet, though mostly from 5,000 to 6,000. The 

 local distribution of the plants and the ex- 

 tent of their numerical development were 

 carefully studied by the author, who is un- 

 able, however, to explain the almost total ab- 

 sence of Guayule in the alluvial soil of the 

 broad playas. He suggests that this fact may 

 be due to the meager aeration of the soil of 

 the playa, and to the possibility of a slight 

 acidity, owing to the presence of a slight 

 quantity of humus. The reviewer has ob- 

 tained results^ that seem to show that the me- 

 chanical conditions of a fine alluvial soil are 

 not unfavorable to the growth of Guayule. 

 But on the other hand it should be noted that 

 the quantity of water-soluble salts is less in 



^American Beview of Tropical Agriculture, 

 May-June, 1910. 



