Contributions to Embryology (Volume 5 )

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1917 Excerpt: ... entirely in the basilar portion of the cell, central to the nucleus. Furthermore, in the stages between 30 and 60 mm. the glycogen globules were present in but small numbers and the glycogen was found in crescentic plaques (fig. 96). This formation of definite plaques is apparently to be ascribed to the fusion of the globules when the amount of glycogen becomes extreme. As far as is known this plaque formation with glycogen has not previously been noted; in one of Goldmann's figures the fusion of some of the globules has apparently taken place. The table on page 94 records the findings in these observations. The occurrence of glycogen in the cells of the chorioid plexus only during a certain portion of embryonic life is, as shown by the foregoing table, a fairly definite phenomenon, but there is surely no indication that this temporary presence of the animal starch bears any relation to the assumption of function on the part of the chorioid plexuses. The evidence afforded by the extraventricular flow of the replaced fluid, with the apparent relationship of the developing chorioid plexuses to the periaxial extension of the fluid, argues strongly against such an assumption. XII. PERIVASCULAR SPACES IN THE EMBRYO. In 1865 His25), using a puncture injection, found that each nerve-cell existed in a so-called space. These pericellular spaces connected, as demonstrated by the flow of the injection mass, with an extensive perivascular network, more complex in its gray matter than in the white. In all of His's cases continuation of the injection led to a peripheral spread toward the pia, both in the spinal medulla and in the brain. Mott(41), working on the brains of animals in which an experimental cerebral anemia had been produced by ligation of the head arteries, ...