GASTRIC ANALYSIS 167 



(2) Fuld and Levison's Method. This test is founded upon the fact, shown by 

 Osborne, that edestin when brought into solution in dilute acid will change in its 

 solubility, due to the contact with the acid, and that a protean called edestan, which 

 is insoluble in neutral fluid, will be formed. The procedure is as follows: Dilute 

 the gastric juice under examination with 20 volumes of water and introduce gradu- 

 ally decreasing volumes of the diluted juice into a series 1 of narrow test-tubes about 

 i cm. in diameter. The measurements of gastric juice may conveniently be made 

 with a i c.c. pipette which is accurately graduated in Koo c.c. Into the first tube 

 in the series may be introduced i c.c. of gastric juice, and the tubes which follow in 

 the series may receive volumes which differ, in each instance, from the volume intro- 

 duced into the preceding tube by Hoo> Ho, Ho, or Ho of a cubic centimeter. 

 Now rapidly introduce into each tube the same volume (e.g., 2 c.c.) of a i :iooo 

 solution of edestin* and place the tubes at 4OC. for one-half hour. At the end of 

 this time stratify ammonium hydroxide upon the contents of each tube, 3 place the 

 tubes in position before a black background and examine them carefully. The 

 ammonium hydroxide, by diffusing into the acid fluid, forms a neutral zone and in 

 this zone will be precipitated any undigested edestan which is present. Select the 

 tube in the series which contains the least amount of gastric juice and which exhibits 

 no ring, signifying that the edestan has been completely digested, and calculate the 

 peptic activity of the gastric juice under examination on the basis of the volume of 

 gastric juice used in this particular tube. 



Calculation. Multiply the number of cubic centimeters of edestin solution used 

 by the dilution to which the gastric juice was originally subjected and divide the 

 volume of gastric juice necessary to completely digest the edestan by this product. 

 For example, if 2 c.c. of the edestin solution was completely digested by 0.25 c.c. 

 of a i : 20 gastric juice we would have the following expression: 0.2 5-?- (20X2) or 

 i : 1 60. This peptic activity may be expressed in several ways, e.g., (a) i : 160 pep- 

 sin; (b) 1 60 pepsin content; (c) 160 parts. 



(3) Rose's Modification 4 of the Jacoby-Solms Method. 5 Dissolve 0.25 gram of 

 the globulin of the ordinary garden pea, 6 Pisum sativum, in 100 c.c. of 10 per cent 



J The longer the series, the more accurate the deductions which may be drawn. 



2 This edestin should be prepared in the usual way (seep. 109), and brought into solution 

 in a dilute hydrochloric acid of approximately the same strength as that which occurs nor- 

 mally in the human stomach. This may be conveniently made by adding 30 c.c. of N/io 

 hydrochloric acid to 70 c.c. of water. Ordinarily it should not take longer than one minute 

 to introduce the edestin solution into the entire series of tubes. However, if the edestin is 

 added to the tubes in the same order as the ammonium hydroxide is afterward stratified, no 

 appreciable error is introduced. 



3 Making the stratification in the same order as the edestin solution was added. 



4 Rose: Archives of Internal Medicine, 5, 459, 1910. 



5 Solms: Zeitschrift fur klinische Medizin, 64, 159, 1907. 



6 The globulin may be prepared as follows: "The finely ground peas, freed as much as 

 possible from the outer coating, are repeatedly extracted with large quantities of 10 per cent 

 sodium chloride solution, the extracts combined, strained through fine bolting-cloth, and 

 allowed to stand over night in large cylinders to deposit insoluble matter. ^ The supernatant 

 fluid is siphoned off and saturated with ammonium sulphate. The precipitate of albumin 

 and globulin is filtered off, suspended in a little water, and dialyzed in running water for 

 three days, until the salt has been removed, and the albumins have been dissolved. The 

 globulins are filtered off and washed two or three times to remove the last trace of albumins. 

 To purify further, the precipitate is extracted with 10 per cent sodium chloride solution, and 

 filtered until perfectly clear. The resulting solution is neutralized to litmus paper by the 

 cautious addition of dilute sodium hydroxide, and again dialyzed in running water for three 

 days to remove the salts completely. The precipitated globulins are then filtered off and 

 dried on a water-bath at 40 C. During the entire process of separation the proteins should 

 be preserved with a mixture of alcoholic thymol and toluol." This dried globulin is used in 

 the clinical procedure. 



