It is thus plainly evident, in view of the ready cleavage of the hemi-group into amido-acids, that the primary products of trypsin-proteolysis, the proteoses and peptones, must necessarily be composed in great part of those complex and semi-resistant atoms which we include under the head of the anti-group. However much one may be skeptical about the real existence of so-called hemi- and anti-groups, there is no gainsaying the fact that a given weight of native proteid, like egg-albumin or blood-fibrin, cannot be converted wholly into crystalline or other simple products by trypsin; indeed, it is quite significant that at the end of a long-continued treatment with an alkaline solution of the pancreatic ferment, there is usually found about fifty per cent, of peptone, while the other fifty per cent. of the proteid is represented mainly by more soluble products, such as the amido-acids. It is also significant that the peptone obtained from an artificial pancreatic digestion, where the proteolytic action has been long-continued and vigorous, resists the further action of the ferment. In other words, it is the so-called antipeptone. In line with this result is the fact that the peptones formed in pepsin-proteolysis, when treated with an alkaline solution of trypsin, are converted into amido-acids and other bodies of simple constitution to the extent of about fifty per cent. This is easily explainable on the ground that the hemi-portions of the above peptones are broken down into simple products, while the anti-portions remain unchanged, being resistant to the ferment and thus leading to a separation of the two groups, or at least to the isolation of the anti-molecules. There is much that might be cited in further support of these views, but doubtless I have said enough to make it plainly evident that in the pancreatic digestion of any native proteid, not more than one-half can at the most be transformed into crystalline products, while the other half will be represented mainly by a peptone incapable of further change by trypsin. Similarly, the products of pepsin-proteolysis exposed to the action of trypsin may undergo a like separation, the hemi-groups only breaking down into simple products. Hence, the whole theory of the hemi- and anti-moieties of the proteid molecule means simply that of the many complex atoms composing the molecule, one-half are easily decomposable by the pancreatic ferment, while the other half are more resistant and make up the so-called anti-group.