GENERAL PROPERTIES AND REACTIONS OF PROTEIDS, 45 



inuria, in which the urine on standing deposited the proteid matter jri a 

 crystalline form (see Fig. 10). They considered it to be of the nature of 

 a globulin. Huppert l has questioned this conclusion, and thinks it pro- 

 bable that the proteid was heteroalbumose. 



It is not, therefore, upon the non-crystalline character of proteid, but 

 upon the enormous size of the proteid molecules, whether crystalline 

 or non-crystalline, that the difficulty of diffusion depends. It thus 

 becomes interesting to inquire into the diffusibility of the proteids of 

 lower molecular weight, namely, the proteoses and peptones. Peptones 

 are diffusible ; this has long been known ; they are highly diffusible 

 compared to albumin, but of low diffusibility as compared with salt. 



FIG. 10. Proteid crystals from human urine. After Byrom Bramwell and Noel Paton. 



The diffusibility of the proteoses has long been inferred, but it is only 

 quite recently that it has been accurately made out that they are inter- 

 mediate in this character between peptones and albumins. The work 

 in this direction was done independently by Kuhne 2 and Chittenden, 3 

 and both arrived at the same results. A curious fact found was, that 

 deuteroproteose (generally regarded as intermediate between the other 

 proteoses and peptones) is less diffusible than protoproteose. But this 



1 Ztschr.f. physioL Chcm., Strassbnrg, 1896, Bd. xxii. S. 500. 



2 Ztschr.f. Biol., Miinchen, Bd. xxix. S. 1. 



3 Journ.'Physiol., Cambridge and London, vol. xiv. p. 483. 



