The fact that we have so many representatives of the hemi-group in this decomposition is significant of the readiness with which the so-called hemi-group undergoes change. All of its members are prone to suffer hydration and cleavage, passing through successive stages until leucin, tyrosin, and other simple bodies are reached. These, and other similar crystalline bodies, are likewise the typical end-products of proteolysis by trypsin, and presumably come directly from the breaking-down of hemipeptone. Antipeptone, on the other hand, is incapable of further change by the proteolytic ferment trypsin. Hence, the hemi-group can be identified by the behavior of the body containing it toward trypsin; _i.e._, it will ultimately yield leucin, tyrosin, and other bodies of simple constitution to be spoken of later on. The anti-group, however, will show its presence by a certain degree of resistance to the action of trypsin, antipeptone being the final product of its transformation by this agent; _i.e._, leucin, tyrosin, etc., will not result. In this hydrolytic cleavage of proteids the anti-group does not always appear as antialbumid. It may make its appearance in the form of some related body, the exact character of the product being dependent in great part upon the nature of the hydrolytic agent, but in every case the characteristics of the anti-group will come to the surface when the body is subjected to the action of trypsin. The above-described treatment of a coagulated proteid with water containing sulphuric acid evidently induces profound changes in the proteid molecule. The conditions are certainly such as favor hydration, and in the case of complex molecules, like the proteids, cleavage might naturally be expected to follow. Analysis of antialbumid from various sources plainly shows that its formation is accompanied by marked chemical changes. Thus, the following data, showing the composition of antialbumid formed from egg-albumin and serum-albumin by the action of dilute sulphuric acid at 100° C., gives tangible expression to the extent of this change: =========================================================== | |Antialbumid[87]| | Antialbumid[87] | Egg- | from | Serum- | from |albumin.| egg-albumin. |albumin.| serum-albumin. --------+--------+---------------+--------+---------------- C.......| 52.33 | 53.79 | 53.05 | 54.51 H.......| 6.98 | 7.08 | 6.85 | 7.27 N.......| 15.84 | 14.55 | 16.04 | 14.31 --------+--------+---------------+--------+---------------- [87] Kühne und Chittenden: Zeitschr. f. Biol., Band 19, pp. 167 and 178.