The human brain : histological and coarse methods of research : a manual for students and asylum medical officers / by W. Bevan Lewis.

  • Lewis, William Bevan, 1847-1929.
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: The human brain : histological and coarse methods of research : a manual for students and asylum medical officers / by W. Bevan Lewis. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    empty themselves into the venous system, may in part explain this appearance, and caution is necessary, lest we hastily assume that this state is the result of morbid activity. The student should, therefore, examine closely the injected part by the microscope, and look for evidence of minute extrava- sations, hsematine crystals, and staining as well as broken- down texture, or other results of inflammatory action and of congestion. This blotchy red aspect of the cortex reappears very frequently in the medulla in similar cases, and is indica- tive of engorgement of the minute capillaries of these regions. 3. Puncta Vasculosa.—It is customary, in judging of the degree of engorgement of the vessels of the white matter, to be guided by the paucity or abundance of the puncta vascu- losa, caused by section of the engorged channels—in other words, the number of drops of blood oozing from the divided vessels are supposed to form some criterion of the engorged condition of the vascular system here. It has been shown by Niemeyer that this is no safe criterion, as 1st. The number of puncta vasculosa vary greatly with the fluidity of the blood, which is an important element in their causation. 2nd. They are often almost entirely absent when we have had indisputable evidence of intense vascular engorgement during life. We must, therefore, be on our guard against attributing too much importance to abundant bloody points on section of the medulla, whilst we should never fail to note whether this condition is or is not associated with distension of the minute capillaries as indicated by fine diffuse patchy redness. I need not here dwell upon the changes of colour due to inflammatory action, as these have been already disposed of when illustrating anomalies of consistence; but I must here repeat the important caution that the student be not misled by expecting to find engorgement and redness in all cases of encephalitis. The larger number of such cases present no undue red coloration.