August 25, 1911] 



SCIENCE 



255 



The three classes of organic foodstuffs consid- 

 ered and the role each plays in the nutrition of 

 the body. Proteids are the principles from which 

 all living cells are made, while the carbohydrates 

 and fats serve as the natural fuel foodstuffs of 

 the body. 



Digestion considered as a chemical process and 

 can be brought about by pure chemical means, but 

 much more slowly than by the digestive enzymes 

 or ferments. 



Enzymatic activity considered. Characteristics 

 peculiar to the enzymes: (1) distinctly specific 

 in their activity, (2) their reactions are incom- 

 plete, (3) reactive to environment, (4) the Mnd 

 of proteid, albumenoid or starch acted upon a big 

 factor in the ultimate amount digested. 



The enzyme pepsin considered; showing by ex- 

 periment that the fresh egg of the epicure and 

 housekeeper is not so easily digested as one from 

 five days to one week old. 



The enzyme panereatin considered. 



The two assays of the pharmacopoeia discussed 

 and a third assay recommended which measures 

 the amount of steapsin or the fat splitting enzyme 

 present. 



Pancreatin is more active upon corn starch than 

 upon potato starch. 



The enzyme rennet and a method recommended 

 for its standardization. As in the animal kingdom 

 we have juices whose specific function is to tear 

 asunder the food material to make it available for 

 the needs of the body, so in the plant kingdom we 

 find analogous enzymes whose function is exactly 

 the same, that is, to render the plant foods as- 

 similable. Most important of these from our 

 standpoint are bromelin and papain. Bromelin is 

 the enzyme existing in the fruit of the pineapple. 

 Papain exists in the fruit of the pawpaw, a tree 

 growing in the Bahamas and West Indies. Collec- 

 tion of papain described and an assay recom- 

 mended by means of which the amount of raw 

 beef digested by the papain in a definite period of 

 time is determined. 



Conclusions — (1) The composition of the white 

 of the egg, chemically and probably even phys- 

 ically, when used for the assay of pepsin, has a 

 great bearing upon the apparent strength of this 

 ferment. The albumen seems to be more difficult 

 to digest the first twenty-four hours after the egg 

 is laid, and a change gradually takes place until 

 after about five to seven days it has reached its 

 maximum solvent condition. After this period its 

 digestibility gradually diminishes. 



(2) In the assay of pancreatin for starch hy- 

 drolysis, as well as all the diastasic ferments, the 

 kind of starch used is of prime importance, and in 

 stating the strength of each it should be in terms 

 of the particular starch employed. 



(3) The papain seems to be equally active on 

 any kind of raw beef when acting in an acid 

 media, but if the character of the beef is changed, 

 as, for instance, by cooking, papain loses its 

 solvent action upon the proteid. 



(4) Eeunet is influenced, in testing its coagu- 

 lating power, by: the condition of the milk, its 

 chemical composition such as the presence and 

 quantities of inorganic salts, particularly those of 

 calcium; the manner of mixing the rennet with 

 the milk; the brand of cows from which the milk 

 is taken, and, lastly, the temperature at which the 

 milk was kept before using and during the test. 



Plmrmacopwial Revision: Joseph P. Eemington. 



Investigation made with Dry Egg Albumin, in 

 View of Replacing the Albumin Coagulated in 

 the Egg, for Greater Accuracy in the U. S. 

 Fharmacopceia Pepsin Assay: A. Zimmerman. 



Laboratory Studies of Pepsin, Pancreatin and 

 Combinations of these Ferments: A. Zimmer- 

 man. 



Precipitated Sulphur, a Study of a Dermatological 

 Prescription: Edw. Kbemeks. 



The Moisture Content of Drugs: Edw. Kremeks. 



A Study of the Bromine and lodometric Methods 



for the Determination of Besorcinol: C. M. 



Peircb. 



The lodometric method is of little value. The 

 bromine method gives good results only under 

 certain conditions. 



Too large an excess of KI causes some decom- 

 position of tri-brom-resorcinol. Considerable dilu- 

 tion before addition of Kit causes precipitate to 

 dissolve, permits a rapid reversal of tri-brom- 

 resorcinol brom and counteracts tendency for de- 

 composition of tri-brom-resorcinol. 



The bromine methods as recommended for de- 

 termination of resorcinol in commercial resorcinol 

 is briefly as follows: prepare a 500 e.c. aqueous, 

 volumetric solution containing 1.4563 g. resorcinol;. 

 withdraw 25 c.c. portions; dilute with 500 e.c. 

 water; add 5 e.c. HCl and let set 1 minute; dilute 

 with 200 c.c. water; add 5 c.c. KI 20 per cent, and 

 let set 5 minutes; titrate liberated iodine with 

 N/10 thiosulphate using starch as indicator. The- 

 number of cubic centimeters of N/10 Br consumed 

 divided by .4 gives percentage of resorcinol. 



