68 EXPERIMENT STATION RECORD, 



tendency of a tissue metabolite to accumulate in and also to be eliminated from 

 the cell in wliich it has been manufactured ; " its ability when eliminated from 

 the first cell to enter into and accumulate in other cells or to be immediately 

 excreted through the kidney, no doubt bears some relatioai to its power of com- 

 bination with tissue colloids. . . . Specific chemical alhnities very probably 

 play a role and the present investigation was undertaken to determine to what 

 extent the phosphatids possess the power of combining with products of tissue 

 metabolism." 



Some of the conclusions follow, which were drawn from experiments with 

 substances which may be regarded as of food value to the tissues, including 

 amino acids, glycocoll, find glucose, and with substances having a characteristic 

 physiological action, including among others adrenalin, caffein, and theobromin : 



" The changes in state of aggregation of lecithin produced by sodium chlorld 

 are the result of the independent action of the sodium nud chlorin ions, whose 

 effects are in opposite directions. Below the concentration of a physiological 

 salt solution (0.12 molecular) the action of the chlorin ion, which decreases the 

 state of aggregation of the lecithin, predominates. Above the concentration 

 of a physiological salt solution, the action of the sodium ion, which tends 

 to increase the state of aggregation of lecithin, comes more and more into 

 prominence. 



" It has been suggested that, when the phenomenon of chlorid retention 

 occurs, some change has taken place in the state of aggregation of the cell 

 lipoids which allows this action of the chlorin ion to predominate to a still 

 greater extent. 



"Ammonia and bile salts possess the power of altering the physical state of 

 aggregation of lecithin to such an extent as to permit of the conclusion that 

 they can be of functional significance in altering the permeability of cell mem- 

 branes. . . . 



" The ability of the tissue metabolites to combine with lecithin, as measured 

 by the changes in the physical state of aggregation produced by their presence, 

 is in some cases considerable, in other cases entirely lacking. Thus hypoxan- 

 thin, creatin, creatinin, adrenalin, and ammonia salts show evidence of combi- 

 nation. Inosit is doubtful and urea is negative. 



" The amino acids show varying powers of combination. The dicarboxy- 

 acids, like acids in general, tend to increase the state of aggregation of lecithin." 



The relation between surface area and respiratory exchange, H. Kettner 

 (Die Beziclinngcn dcr KorpcrolierfliicTie zum Rcspiratorisclicn GaswechscL 

 Inaug. Diss., Univ. Bern. 1909, pp. 30, pis. 2, fig. 1). — According to the author's 

 investigations, which were made with young and with older guinea pigs, total 

 carbon dioxid production increases with increased body weight and increased 

 surface area, differences being very much greater when expressed on the per- 

 centage basis per unit of body weight. The experimental data reported are 

 discussed in relation to theories of nutrition. 



ANIMAL PRODUCTION. 



The mineral nutrients in blue grass, E. B. Forbes, A. C. Whittier, and 

 R. C. CoLLisoN (Ohio >^ta. Bui. 222, pp. 30-53).— A study of the nutritive value 

 of the mineral constituents of blue grass (Poa pratensis), with special refer- 

 ence to the content cf phosphorus and the chemical condition in which it is 

 present. 



Blue grass from different localities varied greatly in its content of mineral 

 elements, some pastures in Ohio containing twice as much mineral nutriment as 

 others. Samples at all stages of growth from Ohio and Kentucky varied in 



