The Johns Hopkins Hospital Reports Volume 2 (Paperback)

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. 1913 Excerpt: ...experiment must be compared with 50 and 53 which represent in general a corresponding duration of recovery. It differs from these in (1) The abundance of parenchymal elements. (2) The great predominance of the more highly differentiated cells. (3) The absence of island formation. The rapid development of the large number of cells of the older types (polynuclears, metamyelocytes and normoblasts) corresponds to what is found in the normal adult marrow, when such a marrow is stimulated to increased activity. And so the phenomenon would seem to have its explanation in the persistence of a large number of parenchymal elements capable of further growth and mitotic activity. That is, the aplasia in this case never reached an advanced grade, as it did, for example, in Sections 50-53. Accompanying the rapid increase in parenchymal elements, the white cells of the circulating blood have increased from 840 per cmm. to 3000 per cmni. in the three days following the cessation of injections. GENERAL SUMMARY. Benzol (CaH6) causes a destruction of the specific bone-marrow cells. A series of injections results in an extreme aplasia of the marrow. As in the case of many other poisons, it acts not only as a destructive agent, but also as a stimulaat, and throughout the descending series, stimulation and destruction are constantly associated. At first the former prevails, and the parenchymal elements increase rapidly in numbers (Fig. IV). As in hyperplasias of normal adult marrows, the increase is chiefly in the more highly differentiated cell types. The younger forms, myeloblasts and megaloblasts are less affected. In this hyperplastic marrow, cell destruction is well marked by the end of the second day. From this time on, as successive doses are given, an increasing number o...