92 Biological Scction, American Chemical Society [Oct. 



fluid condition can changes in surface tension be regarded as f actors 

 in the ameboid movement. 



Jensen obtained the figure of 6000 dynes per centimeter by divid- 

 ing the weight sustained, by the circumference of the plasmodium 

 thread. It would have been just as logical to divide the weight sus- 

 tained by a Steel wire, by its circumference and call the quotient the 

 surface tension of the Interface steel-air. 



Countless measurements of the surface tensions of aqueous Solu- 

 tions (against air) have shown that the surface tension of water 

 (about 70 dynes per cm.) cannot be raised very high. Some inor- 

 ganic Salt Solutions have surface tensions against air as high as 85 

 dynes per cm.''' On the other band the surface tension between two 

 Solutions such as isobutyric acid in water and water in isobutyric acid 

 is either nil or very nearly so.^ Jensen's figure falls far outside the 

 figures recorded for aqueous, or for any other type of, Solution, that 

 the writer has seen. 



Consequently, Macallum's use of Jensen's figure and of data 

 based upon it, in bis theory of muscle contraction based upon 

 changes in surface tension in the working muscle, may lead to 

 erroneous results. 



The elimination of zinc. William Salant and J. B. Rieger. 

 (Pharmacological Lahoratory, Bureau of Chemistry, U. S. Dep't of 

 Agriculture, Washington, D. C.) The experiments were made on 

 rabbits. Zinc malate was given intravenousl}^ and zinc acetate sub- 

 cutaneously. The urine collected for periods of 24-48 hours 

 showed the presence of 1-2 mg. of zinc. Much larger amounts were 

 found in the feces and contents of the posterior intestinal canal, 

 after the subcutaneous injections. The quantities of zinc varied 

 between 8.5 and 17.1 mg. in 24-48 hours, which represented 10-34 

 percent of the amounts introduced. The amounts of zinc eliminated 

 by this Channel were greater after intravenous injection, being 17-20 

 mg., or 40 percent of the quantity administered. 



The absorption and fate of tin in the body. William 

 Salant and L. P. Treuthardt. (Pharmacological Lahoratory, 



■^Berg: Biochemical Bulletin, 1912, ii, p. loi. 



«Whatmough: Ztschr. f. physikal. Chem., 1901, xxxix, p. 184; Antonow: 

 Jour. de chimie physique, 1907, v, p. 370. 



