134 LECTURES ON IMMUNITY 



The sign -^ indicates that the decomposition of the di- 

 saccharide by means of yeast is also possible, and this is 

 the normal process. In a similar manner it is possible to 

 reverse this reaction under the influence of sulphuric acid 

 as the catalysor, as was shown by Musculus, Wohl, and 

 Fischer. 



Fischer and Armstrong synthetised isolactose by means 

 of kephir yeast (lactase) from //-glucose and ^/-galactose. 



Kastle and Loewenhart, as well as Hanriot, accomplished 

 the synthesis of ethyl and monoglyceryl butyrate by means 

 of animal lipase ; and Taylor synthetised olein-triglycerid 

 by means of lipase from the castor bean, but he did not suc- 

 ceed in reversing tryptic digestion. 1 Emmerling added a 

 maltase from yeast to a mixture of glucose and nitril man- 

 del glucoside and recovered amygdalin after the lapse 

 of three months. As is seen from these illustrations, the 

 reversibility of processes accelerated by ferments is a 

 normal phenomenon. 



All the experiments cited which give a constant value 

 of qt seem to indicate that even here the reagents dif- 

 fuse into the small particles of the substance examined 

 with such a speed that the time of diffusion may be re- 

 garded as very low compared with the time of reaction. 

 For the erythrocytes and bacteria this may be easily under- 

 stood, because their linear dimensions are very insignifi- 

 cant (cf. p. 25). This may even be the case for the 



1 Quite recently experiments on the synthetic action of trypsin or pepsin 

 seem to have been followed by success. Taylor (Univ. of Calif. Publ., 

 Pathol. I, No. 9, 1907, p. 343) synthetised protamin from its products of 

 decomposition by means of trypsin, and T. Brailsford Robertson (Univ. of 

 Calif. Publ., Pathol. Ill, No. 9, 1907, p. 59) synthetised paranuclein from 

 its products of decomposition by subjecting them to the action of pepsin. 



