758 . EXPERIMENT STATION EECORD. 



The volume and specific weight of the human body, J. Wengleb {Arcli. 

 Physiol. [Pfliiffcr], 115 (1906). No. 11-12. pp. 612-621, fin. J).— Using specially 

 coustvucted apparatus the author measured the volume aud specific gravity of 

 the lumiaii body as it is ordinarily considered and with the exclusion of the 

 included air which is variable in (luantity. According to his results the body 

 volume of the person experimented upon, exclusive of the air contained in the 

 body, Avas 71.7G liters, and the specific gravity of the body substance, air ex- 

 cluded, was l.Of). 



On the influence of neutral salts upon the rate of salivary digestion, 

 Jane B. Patten and P. G. Stiles {Amer. Jour. PhrisioL. 11 {1906), No. 1. pp. 

 26-31). — As shown by the experimental data, ptyalin is .very active in the 

 presence of many salts in high concentration, the effect being observed even in 

 the case of some saturated solutions, notably those of magnesium sulphate and 

 ammonium chlorid. 



" The most striking instances of accelerating effects were obtained with salts 

 of magnesium, calcium, and barium — belonging to a natural chemical group. 

 But with increasing concentration these salts diverge in their behavior, and 

 calcium chlorid at last restrains the enzym, which never becomes true of 

 magnesium sulphate, 



" When we compare the retarding influence of salts of ammonium, potassium, 

 and sodium we find the ammonium compound much less active in checking the 

 digestion than either of the other two. There seems to be no marked difference 

 between the sodium and the potassium salts. Sodium chlorid retards some- 

 what more than does potassium chlorid, and this order holds for the sulphates, 

 but seems to l)e reversed for the benzoates." 



Other (juestions were also considered. 



Investigations in physical chemistry and their relation to digestion 

 and resorption, E. Reiss {Zenthl. Gesam. Plii/siol. ii. Path. Sto-lficcch.scls, n. 

 ser., 1 (1906), Nos. 12, pp. 353-360; 13, pp. 'lOJi-.'iiry, pg. 1; IJ,, pp. !i3S-Ii k1 ) .—^ 

 Recent advances in physical chemistry are sunnuarized and discussed with 

 special reference to the physiology of secretion, resorption, and digestion, aud 

 also the pathology of the subject. 



The chenxistry and biochemistry of creatin and creatinin, O, Folin 

 (Vpsala Lakarefor. Forhandl., n. ser.. 11 {1906), Sup. Ill, pp. 2(J).— Having 

 shown by laboratory experiments that creatin can not be readily converted into 

 creatinin, the author carried on experiments to determine whether the commonly 

 accepted view is tenable that creatin is a waste product of protein metabolism, 

 which is eliminated in the urine in the form of its anhydrid creatinin. 



The conversion of creatin of the food into creatinin was not observed in the 

 body. Neither creatin taken in the food nor the nitrogen equivalent to it was 

 found in the urine when it was taken in a diet low in protein. It was, however, 

 apparently utilized in the body, as none was found in the feces. When taken 

 with a diet rich in pi'otein creatin itself rather than its decomposition products 

 appeared in the urine. 



As a working hypothesis for subsequ^'iit exi)eriments, the author suggests 

 the theory that creatin as distinguished from creatinin is a food and not a 

 waste product. Its behavior is clearly unlike that of an ordinary amino-acid, 

 the nitrogen of which would ai)pear as urea. 



" It is possible that the niti"Ogenous substances which serve to maintain 

 the nitrogen e(iuilibrium in the living tissues are special i)roducts which do 

 not easily take part in the urea-forming processes. Creatin may be one such 

 product, is therefore retained in the general tissues, and consequently we find 

 the muscles rich in creatin. When the organism is daily supplied with an 

 abundance of protein it may then be preparing as much creatin as is needed 



