Febbdart 28, 1919] 



SCIENCE 



217 



by the frequency with which he refers to the 

 subject. With the object of procuring further 

 information he sent his " notice " to Russia, 

 and from Baron von Asch, surgeon in the 

 Kussian army, he learned that in January, 

 February, and March, 1782, a disease described 

 as " febris catarrhalis epidemica benigna " 

 prevailed in the Russian capital. It origi- 

 nated in eastern Siberia, on the Chinese fron- 

 tier, and spread through the whole of Russia. 

 — The British Medical Journal. 



SCIENTIFIC BOOKS 



A Text-iook of Precious Stones. By Fraxk 

 B. Wade, B.S. Published by G. P. Put- 

 nam's Sons, 1918. Svo, pp. xiii + 318. Il- 

 lustrated. 



Those who are familiar with the work on 

 " Diamonds " by the same author will find the 

 present book characterized by similarly attrac- 

 tive features. The style is clear and precise 

 and readability and practicality are afforded 

 by examples drawn from the writer's own ex- 

 perience. 



The book will appeal to the amateur rather 

 than the professional student, but this is prob- 

 ably the intention of the author. His experi- 

 ence as a teacher has doubtless aided him in 

 presenting the subject in a systematic and 

 easily assimilable manner. The physical prop- 

 erties of gems are treated under the various 

 subdivisions of refraction, absorption and di- 

 chroism, specific gravity, luster, hardness, and 

 color, each to tlie extent of one or more chap- 

 ters, and numerous practical details are given 

 in the chapters on testing, cutting, occurrence 

 and imitation of gems. The chapter on 

 "tariff laws" affords useful information not 

 readily found elsewhere and the bibliography 

 of the subject of gems is the most complete 

 and satisfactory for the purposes of the gen- 

 eral reader that the reviewer remembers to 

 have seen. The book is not extensively illus- 

 trated, a few text figures from line drawings 

 comprising all the pictures that are provided. 

 Besides its usefulness for general reading, 

 the title of the book and its systematic plan 

 suggest that it could be employed for more 

 formal inatruction. The wide distribution of 



gems in Nature and their possession in some 

 form in almost every home, make it probable 

 that they could be used more extensively than 

 is now the case as a basis for school study. 



The reviewer finds little to criticize adversely 

 in the book beyond the occasional use of the 

 term " gemology." While this term might be 

 generally understood to refer to the science of 

 of gems, it is incorrectly formed for this pur- 

 pose and in reality has quite a different mean- 

 ing. The Greeks seem to have had no single 

 term for distinguishing objects used for the 

 purposes for which we use gems, but indicated 

 things of value by the adjective tiVios. Pre- 

 fixing this adjective to X.i6<K, stone, the term 

 tiniolithology can be obtained, which is at 

 least a word properly formed to indicate the 

 science of gems. 



Oliver C. Farrington 



Field Museum of Natural History 



SPECIAL ARTICLES 



PINK ROOT OF ONIONS 



In 1915 Professor F. W. Mally called the 

 writer's attention to a very serious disease of 

 onions in Webb County, Texas, and locally 

 known as pink root. Investigations were be- 

 gun on this disease with Professor Mally, who 

 cooperated in the field experiments and offered 

 valuable assistance in many ways. A search in 

 literature showed that there were no records 

 that could be found, where mention was made 

 of tliis new plant trouble. From conversation 

 with Professor Mally I was told that Professor 

 W. M. Gilbert, of the United States Depart- 

 ment of Agriculture, had at one time worked 

 on this disease and also published an account 

 of the same. However, a letter received from 

 Professor Gilbert dated !May 15, 1918, says as 

 follows : " So far as I know there are no pub- 

 lications on this disease, as I did not do 

 enough work on it to secure results for pub- 

 lication and have not had the opjwrtunity. to 

 study it very recently." The writer was the 

 first to report on this disease in 1917.' 



1 Taubenhaus, J. J., "Pink Root, a New Disease 

 of Onions in Texas," Phytopath. 7: 59, 1917 (ab- 

 stract). 



