CHANGES ACCOMPANYING BREAKING OF REST PERIOD 31 



this discussion, but it should be borne in mind that only a few 

 determinations were made. 



These experiments were carried out as follows: A gelatin 

 solution was prepared by adding 20 gr. pure gelatin to 100 cc. luke- 

 warm water. Each of a number of similar vials received 25 cc. of 

 this solution. After the gelatin had hardened, a set of material for 

 the experiment was prepared as follows: In one vial was placed 5 

 gr. of treated apple cortex; in another, 5 gr. of untreated cortex; in 

 another, 5 gr. treated cortex that had been heated to 100 C., and 

 in still another, 5 gr. untreated cortex which had been heated to 

 100 C. Next, 25 cc. of pure water sufficient to cover the cortex 

 material was added to each vial. Also the same quantity of water 

 was added to other vials which contained gelatin but no cortex 

 material. Toluene was added in all cases to prevent bacterial 

 activity. The series was run in duplicate. The material was 

 allowed to act for twenty-four hours at 20 C. 



The amount of solidified gelatin remaining at the end of the 

 period was used as an index to the proteolytic enzyme activity. 1 



The results of the test showed very clearly that the ether 

 treatment increased the proteolytic enzyme activity as the least 

 amount of the solid gelatin remained in the vials which contained 

 the unheated cortex from etherized twigs. Very little of the gelatin 

 had liquified in the vials containing water but no cortex. 



The experiments were varied by allowing the cortex material 

 to act on one cm. cubes of gelatin. Again the etherized material 

 showed most action. 



3. Fat Splitting Ferments. A series of experiments were 

 carried out to determine whether the fat splitting enzymes of the 

 twig tissue were influenced by agents which break the rest period. 

 The results of these tests are not given as being conclusive since too 

 few experiments were made. 



The material used for these determinations was cortex from 

 apple and ash twigs. A series of vials were prepared in duplicate as 

 follows : 



la and Ib. 5 gr. cortex from etherized twigs plus 25 cc. castor 



oil emulsion. 

 2a and 2b. 5 gr. cortex from untreated twigs plus 25 cc. castor 



oil emulsion. 



3a and 3b. 5 gr. heated cortex from etherized twigs plus 25 

 cc. castor oil emulsion. 



1. Fermi, C. On the Presence of Enzymes. Centbl. Bakt. 2 Abt. 26. 

 (1910) pp. 330-334. 



