( 36 ) 



the transformation of trvpsinop:en into trypsin, resp. of promoting it ^). 



I Imrc liiu'ii, pcrfrclhi nhjc to conlirm HeidEMIAIn'.v iiu't'sf(i/t(t(o/is, hut 

 si/sfcni'itic rcsi'ai-ckcs luirc sIkhi'ii nii\ th'it fhi^ii <in' oiihj iiniildhh' for 

 (lhir(;rui(;-i'.di'iict.'i f rum the ylaitd, hut in no //v.>r for n'(ftt'rij e.rtrfirfs 

 or for the pressed out juice of the jKincreds. 



From the great iiiimlter of experiments w liieli I have made to this 

 end, and Avhich alwavs led to the same resnlts, I sliall state here a 

 single scries. 



First a repetition of Hkide.nhainV ex|»eriment. The method whieh 

 IIkidenhain indicates is as foHows: 



To everv gram of |)anereassnl)staiiee, wliich has heen ent into 

 small pieees and snhjeeted to pressnre, is added 1 e.e. aeetie aeid of 

 l"„. The mass is again rnlthed for 10 minutes, and the tims ol)tained 

 compnund then ndxed with Id grams of glycerine. After 3 days this 

 compound is tillei'ed. 1 now composed a glycerine-extract according 

 to this prescrij)tion and, along Avith this, other glycerine-extracts 

 wherehy instead of J cc. acetic acid of l"/„, 1 took i'es[)ectively 1 c.c. 

 acetic acid of 2\/.^ "/o» J ^'•^'- i^cetic acid of 0.5 "/„ and '1 c.c. water. 



The licrehy ohtained extracts 1 allowed to act on while of egg 

 Avithout water (Col. 11) and also after addition of water ((Join uni 111) "-). 



It is seen that where the glycerin-extracts of (V)l. I ai-e lirought 

 to act on white of egg no digestion a|)pears after 3 days (Col. II). 

 This had to he expected. F\en if trypsin had heen set \\'iH'. it could 

 not have woi-ked actixely in the pni-e glycerine; tor it is well-known 

 that trypsin is not solid)le in pure glycerine. Trypsin is liheivited 

 however when the glycerine-exti-acts ai'e diluted with water (Col. Ill) 

 and more so with th(»se extracts which are ccmiposed with acetic 

 acid (1, 2, 8) than, in those irhere ordtnurij initee iras used 4). The 

 acetic acid therefore furthers the liheration of the trypsin in glycerin- 

 mixtures with water. A pi-o])ortion between the concentration of 

 the acetic acid and the extern of its operative power, does not exist 

 however. 



It could iKwv l»e suggested that the trypsin from Col. Ill in Tahle I, 

 wliich was at first inactive being in an nidissoluble condition, now 



^) I only mention here: Hamm.vustln, Lelubueh def pliy.siol. Cliemic, 181*11. icf 

 Druck, pag. 295. 



A. Gamgee, (Deulsihe Ausgabe von Asher und Beyer), Die Physiol. Clliemic 

 (ler Veidauung. 1897, pag. 231. 



(J. Oppenheimer, Die Feimeute und ilini- Wiikungen, 19U0. }i. 71 and llG. 

 -) For the quantitative determination of the proteolytic digestion the method of 

 Mett was followed. The experiments were only made with pig's pancreas. The 

 temperature ot the incubator varied from 37 to 39° C 



