GENERAL PROPERTIES AND RE A CTIONS OF PROTEIDS. 45 
inuria, in which the urine on standing deposited the proteid matter in a 
crystalline form (see Fig. 10). They considered it to be of the nature of 
a globulin. Huppert 1 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 lias 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 BramweU 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. C'hcm., Strassbnrg, 1S96, Bd. xxii. S. 500. 
2 Ztschr. f. Biol., Miinchen, Bd. xxix. S. 1. 
3 Journ. Physiol., Cambridge and London, vol. xiv. p. 483. 
