47 



Table 8. 

 Control on the experiments of table 8. 



In all these titrations I used phenolphthalein as an indicator. 



This control experiment shows clearly that the acidity develop- 

 ped, may be due to other than fatty acids, resulting may be 

 from autolytical phenomena. Remarkably enough Chapeaux 

 found such digests alcaline. 



The next thing to do was to try separating out the olive 

 oil plus formed fatty acids from the material. This was done 

 by extraction with liberal quantities of ether; the ether was 

 evaporated away from the extract and a titration was made. A 

 control-titration was also made on the same amount of olive oil. 



The result of these titrations gave me more courage again 

 and made it probable that at least part of the acidity might be 

 caused by fatty acids. 



Table 9. 

 Titrations of ether extracts. 



One more control was necessary however. It should be proved 

 that the „other acid" was insoluble in ether, in other words, 

 the same proceedure should be repeated while no olive oil had 

 been added. For this purpose I used the material which had 

 been used for the autolysis experiments of p. 26. A large amount 

 of this material, containing many more radial sacs than the other 

 digests, was extracted with ether in exactly the same way. The 

 final titration gave 12.80 c.c. of twentieth normal alcali. 



From these critical experiments one can see how careful we 

 must be in judging about the presence of lipolytic enzymes in 

 our group. These difficulties have not been seen by other authors 

 who have been working on our group; for this reason I am 

 inchned not to take their results too seriously. The formation 

 of an acid of some kind in these digests of the radial sacs. 



