June 30, 1911] 



SCIENCE 



1005 



believe, are a manifestation of the same actinic 

 effects that we have long been familiar with 

 in certain inorganic substances. Indeed, be- 

 ginning with the red rays of light at one end 

 of the scale and ending with the hardest X- 

 rays and gamma rays at the other, we find 

 physiological effects differing chiefly in de- 

 gree and corresponding in intensity with the 

 actinic strength of the respective rays. 



What the bio-chemical processes are that 

 are set going by radium, or by the more fa- 

 miliar forms of actinic energy, we are in no 

 position to say. From experiments with 

 radium upon eggs Schwartz proposed that all 

 of the effects of radium upon tissues were 

 due to decomposition of lecithin. Hussakof 

 suggests from experiments of Willcock, Zuel- 

 zer and Kornicke that oxygen in some not 

 understood way seems to play a part in the 

 process. There is every reason to believe that 

 the process is not explicable by any simple 

 chemical reaction. Radium rays do not pro- 

 duce an immediate effect upon living tissues, 

 similar to the reduction of silver salts, for 

 example. They have an effect upon the life 

 processes of the cells, and these after a rela- 

 tively long time produce the results that we 

 recognize as a radium reaction. In other 

 words the process is a vital process, and one, 

 doubtless, involving all of the chemical com- 

 plexity of cell life itself. 



BIBLIOGRAPHY 



HussAKOP, Louis. Medical Mecord, July 20, 1907. 

 Action of radium on plants and animals (full 

 summary and bibliograpliy). 



Halkin. Archiv f. Dermat. und Syph., 1903, 

 LXV., p. 201 (histology). 



DoMiNici and Barcat. "Archives des Maladies 

 du cffiur, des vaiseux et du sang, 1908 ' ' 

 (histology). 



DoMlNici. Archives Generales de Medicine, July, 

 1909 (histology). 



GuiLLEMONT. "Archives of the Bontgen Bay," 

 Vol. XV., No. 3, August, 1910. (Effects on 

 seeds and plants and biochemistry.) 



Barling. Brit. Med. Jour., July 30, 1910 (his- 

 tological effects on malignant growths). 



Wm. Allen Pusey 



University of Illinois 



SPECIAL ARTICLES 



ON THE CLASSIFICATION OF SAND GRAINS 



Professor W. H. Sherzer has just pub- 

 lished an important paper containing a 

 classification of sands^ in which a successful 

 attempt is made to use origin as the primary 

 factor for determining subdivisions. I say 

 successful, because I believe Sherzer's classi- 

 fication to be a sound one for the reason that 

 it is a natural one. In detail, as he himself 

 says, it requires further amplification, but I 

 believe that its leading features will stand. 

 He distinguishes the following types : 

 (1) Glacial sand type, (2) volcanic sand type, 

 (3) residual sand type, (4) aqueous sand 

 type, (5) ceolian sand type, (7) organic sand 

 type, (8) concentration sand type. The first 

 five of these are clastic, the others are non- 

 clastic. To the clastic he might have added 

 as number 6 the artificially produced sands 

 (or mechanico-organic) which no classifica- 

 tion can afford to neglect, and to the non- 

 clastic might be added, for completeness sake, 

 (9) the granular snow and the firn or neve, 

 precipitated from the atmosphere, and (10) 

 lapilli of igneous origin, but not pyroclastic. 

 With the glacial sand group (1) Sherzer 

 compares those formed by avalanches and rock 

 slides, by rock and mud flows, and by earth 

 movements along joint planes, i. e., the fa- 

 miliar fault SEmd. He also adds the sand 

 produced in the manufacture of talus, but 

 this, when not due to mechanical slipping, 

 clearly belongs under his residual type. 



As thus included, the mechanical abrasion 

 sands : glacial, fault, etc., come under the 

 heading of autoclastic sands, and the series 

 given by Sherzer, with the addition of the 

 artificial sands, corresponds exactly to sub- 

 divisions of clastic rocks which I published 

 in 1904,^ as shown in the following table, 

 where the corresponding divisions of my 



^ W. H. Sherzer, ' ' Criteria for the Eecognition 

 of the Various Types of Sandgrains, " Bull. Geol. 

 Sac. America, Vol. 21, No. 4, pp. 625-662, pis. 

 43-47. 



^A. W. Grabau, "On the Classification of Sedi- 

 mentary Rocks," American Geologist, Vol. 23, pp. 

 228-247, AprU, 1904. 



