Below the Truemmerfeld is the _Geruestmark or framework marrow_, another distinguishing feature of scurvy. This extends for about 5 to 10 mm. toward the lymphoid marrow, where it ends more or less abruptly. It is composed of a loosely-constructed fibrillar tissue on a gelatinous-appearing groundwork, of sparsely scattered cells, and bony trabeculæ which are markedly thin and weak. Here and there are hemorrhages and blood pigment, especially adjacent to the "Truemmerfeld." Another feature which strikes one at first glance is that the entire marrow area is incompletely filled by the thin and greatly-depleted trabeculæ of the spongiosa. The question has been raised whether this rarification is to be considered entirely of scorbutic origin. It is due evidently to a lack of function of the osteoblasts, which are diminished in number, and are represented by a layer of shrivelled spindle cells along the walls of the atrophied bony columns. They may fail almost entirely, as may its osteoid border, which is significant of active bone tissue. The lack of bony structure and rarification clearly is not due to an increase in the number or the function of the osteoclasts, for these do not appear in excess. It is mainly the result of normal bone resorption with a lack of normal bone regeneration. Aschoff and Koch suggest that the framework marrow may be able to manufacture bone, but cannot accomplish this because there is a lack of material from which to make osteoid tissue. This, they believe, constitutes the primary deficiency--a lack or faulty development of cement substance, which in turn may depend on an alteration of colloid material. Regarded in this light, the lesions of the bones resulting in fracture and those of the blood-vessels resulting in rupture and hemorrhage are dependent on a deficiency of the same basic material. [Illustration: FIG. 5.--Infantile scurvy. Epiphyseal junction of lower end of femur: (a) calcified cartilage at "Truemmerfeld"; (b) hemorrhage in the fibrous marrow (Gernest-mark). Bone cortex and trabeculae abnormally thin. McCallums' Text Book of Pathology. W. B. Saunders Co.]