14 MACROMOLECULAR COMPLEXES 



there is apparently space to accommodate water layers ranging up 

 to about 1000 A in thickness. The properties of the system will 

 naturally depend on whether this water is solvent water having the 

 properties of bulk water at the same temperature, or water which, 

 by virtue of the structures of the contiguous condensed regions, has 

 a more or less regular arrangement. Szent-Gyorgyi (1956) has 

 recently considered the importance of water structure and has per- 

 formed several intriguing experiments which suggest that water in 

 the biological system may have predominantly an icelike structure. 

 Kauzmann (1959), in a review of protein denaturation, discusses 

 the formation of icebergs around non-polar groups, as well as the 

 short-range interactions of interest here. The evidence presented by 

 Kauzmann suggests that the ordering of water molecules is con- 

 fined to the locality producing the ordering and is not transmitted 

 beyond a few Angstroms. 



If we restrict ourselves to considerations of colloidal structure, 

 it is apparent from the foregoing that molecules may, by a variety 

 of short-range interactions, essentially come out of solution and 

 develop condensed regions which, from the principal directions of 

 development, would be classified as rodlets, filaments, lamellae, 

 platelets, etc. One of the systems, involving the development of 

 collagen filaments, not only may illustrate the relationships between 

 size and long-range interaction but suggests the possibility of spe- 

 cific long-range interactions. This system, the basement lamella 

 lining the skin of amphibian larvae, has been treated bv Weiss 

 (1957). In the region of the basement lamella there are approxi- 

 mately 20 layers, each 2000 A in depth. Each laver contains a 

 system of rods, tentativelv identified as collagen, which are 500 A in 

 diameter and cross-striated at 520 A intervals. Within any one 

 layer the rods run parallel, with their cross-striations in lateral 

 register. However, the orientation of each laver differs from that 

 of adjoining ones by an angle of 90°. 



If a piece of membrane is excised, the membrane is repaired. 

 During this process there first appear small cross-striated fibrils of 

 about 200 A diameter. These are initially unoriented, but as they 

 grow in length and diameter the particular matched orthogonal 

 pattern is established. If the medium between the oriented fibrils 

 does not contain condensed structures to transmit directions for 

 orientation and for striation matching, the s\'stem stronglv suggests 

 the existence of specific long-range interactions. It is possible that, 



