702 EXPERIMENT STATION EECORD. 



energy liberated by this oxidation of the glucose is assumed to be 58 calories, 

 or 8.6+ per cent of the total energy obtained by the complete combustion of 

 glucose. Calculated approximately, this organism daily converts an amount of 

 energy equivalent to 448.4 calories per kilogram of its weight. 



A method for determining' the electrical conductivity of the interior of 

 tlie cell, R. HoBER (Pfliiger's Arch. PliijsloL, 133 (1910), No. 4-€, pp. 237-253, 

 figs. 7). — The author has worked out a method for measuring the electrical 

 conductivity of the interior of the blood cell within a limit of error of from 

 1 to 2 per cent. 



The principle of the method rests upon the factor of knowing whether or 

 not the capacity of the trough is changed when a cell is brought into the 

 dielectron. In this manner he found that blood corpuscles, which have prac- 

 tically no electrical conductivity when measured according to Kohlrausch's 

 method, have an internal electrical conductivity which corresponds to that of 

 tenth-normal potassium chlorid solution. 



Further observations of the effects of ions on the activity of enzyms, 

 W. N. Berg and W. J. Gies (Proc. 8oc. Expt. Biol, and Med., 4 (1906), No. 1, 

 pp. 17-19). — The authors briefly summarize the results of a study of the 

 peptolysis of many proteins in a given series of acid solutions. That acid 

 molecules are not necessarily inhibitory in peptolysis is apparent from data 

 reported in which acetic acid was used instead of sulphuric acid. 



From the data obtained and the results of similar experiments with acetic 

 acid, the authors conclude that new light is thrown " on the well-known fact 

 that peptolysis is almost negative in solutions of acetic acid alone. This lack 

 of peptolytic efBciency on the part of acetic acid is apparently due to the 

 low hydrion concentration of acetic acid solutions. The acetic acid molecules 

 and anions, in the proportions above indicated, seem to be practically inert. 

 It is obvious that peptolysis is neither favored nor interfered with materially 

 by moderate amounts of acetic acid, a fact which suggests that the purely 

 chemical phases of the normal gastric digestive process are practically unaf- 

 fected by vinegar. Secretoi-y conditions, however, are no doubt modified." 



It is stated that the investigations will be continued. 



The relation between the physiolog'ical effect of ions and their physical- 

 chemical properties, W. N. Berg (Ion, 2 (1910), No. 3-Jf, pp. 161-18S).—A 

 large amount of data is summarized and discussed with reference to theories 

 of physical chemistry. 



The composition of invertase, A. P. Matkews and T. H. Glenn (Jour. Biol. 

 Chem., 9 (1911), No. 1, pp. 29-56). — Invertase prepared from yeast by O'Sulli- 

 van and Tomson's method of self-digestion and precipitation with alcohol was 

 found to consist of a gum, a mannosan, and a nitrogen-containing portion. 

 A rough parallelism was found between activity and nitrogen content. 



"It is suggested that what is ordinarily called invertase is a union of an 

 inactive colloidal gum, with an active protein ferment. The active principle 

 may be an albumose or a coagulable albumin. This union is inert and the 

 ferment is thus tied up in the cell. The union of carrier and enzym constitutes 

 the invertase zymogen. By the action of acid, the ferment is freed from its 

 carrier, the gum, and becomes capable of uniting with and changing its sub- 

 strat. The action of acids in cell physiology, and in hastening the action of 

 invertase and other enzyms is thus partially explained. Diastase would appear 

 to be a union of an albumose enzym with a pentose gum. It is suggested that 

 possibly the ferments are thus anchored and rendered inert in cells by uniting 

 them with colloids. The name ' carrier ' is suggested to cover these colloidal 

 substances, the carriers of the ferments. The carriers appear to be usually 

 of the same chemical nature as the substrat of each ferment and to be colloids. 



