140 



SCIENCE 



[N. S. Vol. LI. No. 1310 



equipment, the instruction, and the research, and 

 the service, in aoeordanoe with the best ideals of 

 modern medical education — as an essential unit of 

 our university plan for development. 



Professor "W. H. Dalrymple has resigned 

 the editorshiip of the Journal of the American 

 Veterinary Association because of his appoint- 

 ment to the deanship of the college of agricul- 

 ture of the Louisiana State University. The 

 nominees for the governorship and the legisla- 

 ture have pledged themselves the support of 

 the (movement for a greater university, in 

 Which movement it is proposed to raise three 

 million dollars for the college of agriculture. 



Dr. Allen E. Stern, of the department of 

 chemistry at the University of Illinois, took 

 charge of the division of physical chemistry 

 at the University of West Virginia, beginning 

 in February. 



Dr. Henry C. Tracy, of the Marquette Med- 

 ical School, has been appointed professor of 

 anatomy at the University of Kansas. 



Dr. C. H. Edmundson, professor of zoology 

 at the University of Oregon, resigned at the 

 close of the fall term to accept the position as 

 head of the department of zoology and director 

 of the research laboratories at the College of 

 Hawaii, Honolulu. 



Professor Clarence Moore has resigned the 

 chair of biology in Dalhousie University, Hali- 

 fax, N. S., and has been succeeded by Pro- 

 fessor Dowell Young, of Cornell University. 



DISCUSSION AND CORRESPONDENCE 



UNRELIABLE EXPERIMENTAL METHODS OF 



DETERMINING THE TOXICITY OF ALKALI 



SALTS 



A METHOD frequently used by investigators 

 of the toxicity of alkali salts is to add certain 

 percentages of salts to soils, plant them to 

 crops and estimate the toxicity by the de- 

 pression of the crop growth. They assume 

 that if sodium carbonate or other salt is added 

 to a pot of soil, that it remains in solution in 

 the soil and that its toxicity can be measured 

 by subsequent crop growth. Very elaborate 

 and expensive experiments have been per- 

 formed based upon this assumption. 



'Now it has been shovra by various investi- 



gators that soils absorb a part, at least, of the 

 salts added, and that the crop growth in these 

 treated soils is much more closely related to 

 the proportion of alkali salts recoverable from 

 the soils than to the proportion of salts which 

 have been added. In other words, the toxicity 

 of salts is not so accurately measured by the 

 amount added to the soil as by the salts 

 recoverable by analysis after the treatments 

 have been made. 



Two papers have been published in the 

 Journal of Agricultural Research which illus- 

 trate the erroneous conclusions that may be 

 reached when toxicity is determined by the 

 per cent, of salts added, viz., " Effect of alkali 

 salts in soils on the germination and groAvth 

 of crops," by Prank S. Harris, and " Soil 

 factors affecting the toxicity of alkali," by 

 F. S. Harris and D. W. Pittman. In both 

 these investigations the attempt was made to 

 measure the toxicity by correlating crop 

 growth with the amount of salts added. In 

 the first-named paper Mr. Harris reaches the 

 following conclusions which are not in accord- 

 ance with results obtained by other investi- 

 gators. The questionable results quoted below 

 would almost certainly not have been secured 

 had the more accurate method been followed 

 of measuring toxicity by correlating crop 

 growth with the soluble salts found in the 

 soil after the various additions had been made. 



The conclusions which appear to the Avriter 

 to be unjustified are : 



1. " Only about half as much alkali is re- 

 quired to prohibit the growth of crops in sand 

 as in loam." 



Since no analyses were made Mr. Harris 

 did not know how much alkali was contained 

 in the soil solution in either sand or loam and 

 the conclusion is therefore unjustifiable. 



2. " Results obtained in solution cultures 

 for the toxicity of alkali salts do not always 

 hold when salts are applied to the soil." 



This statement may be true but his experi- 

 ments do not warrant the drawing of such a 

 conclusion for here again the author did not 

 determine the concentrations of the soil solu- 

 tions and he therefore has no basis for com- 

 paring the toxicity of salts in solution cul- 



