CHAP. II.] PEPTONES. 135 



It is found that the proteid ihatters which remain after precipita- 

 tion with ammonium sulphate, and to which it is now proposed to 

 restrict the term peptones, differ from all other bodies, even from the 

 most closely related of the albumoses, by the most important pro- 

 perty which they present, of being able to diffuse with much greater 

 readiness through membranes, and especially through animal mem- 

 branes. This property is obviously of the highest importance from a 

 physiological stand-point, but it is no less so from a physical and 

 chemical point of view, for it establishes, as we have already pointed 

 out, the fact that the true peptones are bodies which differ from 

 proteids in general, and from the albumoses in particular, in possess- 

 ing a smaller molecular weight : that they are certainly products of 

 decomposition, and that whether it be true or false that the changes 

 brought about by the digestive enzymes are of the nature of hydro- 

 lytic decompositions, they are certainly of the nature of decomposi- 

 tions, under the influence of which the giant molecules of the proteids 

 are resolved into molecules so much smaller that they are able to find 

 their way through the interstices of the tissues, and be absorbed. The 

 above considerations warrant us, then, in establishing a distinction 

 between peptones and those bodies which possess many points of 

 resemblance to them. 



It now remains for us to consider the special facts with which we 

 are acquainted relating to the mixed peptones which result from the 

 action of gastric juice, as well as to refer to the history, so far as it is 

 known to us, of the individual peptones. To the mixed peptones, 

 hemipeptone and antipeptone, Kiinne and Chittenden 1 applied the 

 convenient term ampho-peptone, which designates its dual character. 

 Modifying slightly the original scheme suggested by Kuhne 2 the 

 production of ampho-peptone by the action of gastric juice upon 

 proteids is shewn as follows : 



Proteid 

 + Pepsin + acid at 40 C. 



Anti-albumose Hemi-albumose 



Anti-peptone Anti-peptone Hemi-peptone Hemi-peptone 



T -- -- 



Ampho-peptone 



1 Kiihne, 'Weitere Mittheilungen,' &c., p. 9. 



2 "We have designated as ampho-peptone the end product of the digestion of 

 albumin by pepsin and acid." ' Peptone,' by W. Kiihne and R. H. Chittenden. Studies 

 in the Laboratory of Physical Chemistry of Yale University, Vol. n. p. 15. 



