1877.] 



System of the Brain, 



327 



overestimated. These anatomical relationships have had great attention 

 bestowed upon them by continental histologists, and more especially 

 those of the German school. Amongst the more important subjects in 

 which their acumen has served to enlighten ns we may take, as an illus- 

 tration, the demonstration of the intimate connexion existing between 

 the lymph-sacs and perivascular channels of the brain, and the success- 

 ful injection of the former by Obersteiner*. Although several years 

 have elapsed since the publication of Obersteiner's views, the accuracy 

 of his statements has not received that appreciation and acknowledg- 

 ment by English observers which the importance of the subject impera- 

 tively demands, nor does it appear that a critical examination of these 

 " pericellular spaces " has been instituted with the object of finally 

 setting the question at rest. 



In his work on this subject Obersteiner's views are expressed so 

 clearly, and the illustrations are so definite, that little doubt as to their 

 accuracy can, I think, remain on the mind of the unprejudiced reader. 



That his views have not been generally accepted amongst us, I infer 

 from the frequent confusion traceable in the writings of many patho- 

 logists in this country with regard to the relationships of the nerve-cells 

 of the cerebral cortex to theimmedia te environment, from the dubious- 

 ness expressed by others as to the nature of these spaces when observed 

 by them, and, finally, to the error committed by others of referring them 

 to an entirely different source to that which Obersteiner claims for them. 



These are the reasons which have induced me to describe my own 

 investigations on the subject and state my opinion, which, on most 

 points, is strictly in conformity with that of the German observer — full 

 opportunities having been afforded me for confirming his statements 

 and gauging their value in pathological researches. 



Existence of Pericellular Lymph-sacs in the Brain. 



My attention was first attracted to the significance of these spaces by 

 (a) the prevalence, in certain morbid conditions, of numerous nuclei 

 arranged in definite directions around the nerve-cells, (5) the presence 

 of undoubted lymph-corpuscles in clear spaces around the cell, and (c) 

 the appearance of pericellular spaces in healthy brain occasionally where 

 the cells appeared perfectly normal and certainly not atrophic. 



The arrangement of nuclei, above alluded to, is at times most striking, 

 and is especially well seen in the larger nerve-cells of the third layer and 

 the still larger cells found at a lower level in the ascending frontal and 

 ascending parietal convolutions of man, which have been termed giant 

 cells. These cells are undoubtedly normal constituents of the cortical 

 layers, and to a great extent constant elements in these regions. I 

 have represented one of these great nerve-cells in Plate 2. fig. 4. To 



* ,; Ueber einige Lymphrauine iiai Gebirne " (Sitzb. d. k. Akad. d. Wissensch. 1 Abth , 

 Jan.-Heft, 1870). 



