The existence and morphology of pores of the order of 150 A, in radius, within collagen fibrils is delineated. Structural features of collagen from air-dried kangaroo tail tendon, impreO"nated with mercury at a p ress ure of 10,800 psi., are compared with those of fibril s not. exposed to mercury. A helical configuration of sub fibrillar elements is suggested by t~e electron microgaphs of individual fibrils. The possible use of mercury under hydrostattc pressure as a technique in staini ng and

more »

... reserving the structur e of biological materials for electron microscopy is advanced. These findings constitute a .visual c<?nfirm!ltion of the presence and probable size of small pores deduced from theoretical consideratIOns of poresize distributions in collagen and leather, and provide additional information about the shape, location, and arrangement of such pores in collagen fibrils.