66 abstracts: parasitology 



FFjTROLOGY. —Chemical analyses of igneous rocks published from 

 1884 to WIS, inclusive. H. S. Washington. U. S. Geological 

 Survey Professional Paper 99. Pp. 1201, with 3 figures. 1917. 



This paper is a revision and expansion of Professional Paper 14, 

 published in 1903. In the introductory text the characters of rock 

 anal3^ses are discussed under the heads of representativeness of the. 

 sample analyzed and the accuracy and completeness of the analysis. 

 The chief errors, both of commission and omission, to which rock 

 analyses are hable are described, and the scheme for rating analyses as 

 to their quahty, adopted in the work, is explained. 



It has been the aim to make the present collection as complete and 

 accurate as possible and, in a sense, definitive. The search through 

 the Hterature, a list of the pubhcations examined being given, has 

 been very extensive, and in this the library of the U. S, Geological 

 Survey has been the main reliance. The number of analyses collected 

 in the tables amounts to 8602, as against 2881 in the previous collec- 

 tion, which analyses are included in the present work. A great im- 

 provement in quality over the earlier work is manifest. The tables, 

 which occupy 1098 pages, are divided into four parts: superior analyses 

 of fresh rocks; incomplete but otherwise superior analyses of fresh 

 rocks; superior analyses of altered rocks and tuffs; and inferior analyses. 

 The analyses in Part I are arranged according to the Quantitative 

 Classification and the norm of each, every one of which has been recal- 

 culated, is given. A discussion of the rules for naming and of some of 

 the names of this system is to be found in the text. 



In appendixes are presented a description of the Quantitative Classi- 

 fication, with a tabular presentation of its divisions and names, a 

 description of the method of calculating the norm, as well as the tables 

 for the calculation of the molecular numbers of the chemical compo- 

 nents and percentages of mineral molecules. H. S. W. 



PARASITOLOGY. — Recent progress in the development of tnethods for 

 the control and treatment of parasites of live stock. B. H. Ransom. 

 Proc. Second Pan-Amer. Sci. Congr. 3: 709-718. 1917. 

 Brief review with list of references. B. H. R. 



PARASITOLOGY. — The sheep tick and its eradication bp dipping. 



Marion Imes. U. S. Dept. Agr. Farmers' Bulletin 798, 31 pp., 



figs. 1-15. May, 1917. 

 A popular discussion with details of methods of control and 

 eradication. B. H. Ransom. 



