ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 171 



Minute Structure of Choroid Plexus in Frog. — R. Collin and 

 J. Baudot {Gomptes Rendus Soc. Biol., 1920, 83, 1143-5). The 

 epithelial covering of the thalamencephalon consists of a club-shaped 

 nodule (the paraphysis or superior choroid plexus) and two bunches of 

 digifciform villosities (the median and inferior choroid plexuses). The 

 epithelial cells of the villosities are prismatic ciliated cells, in contact 

 basally with a collagenous zone resting on the endothelial wall of capil- 

 laries. Their minute structure is described. The paraphysis proper is 

 formed of endothelial capillary tubes covered with cubical cells, which 

 have no cilia. J. A. T. 



Hiwatari, Kazuo. — " Uber das Wesen des Trachoms nebst einem 

 Beitrag zur normalen Histologic der Conjunctiva " (Actfe Scholae 

 Medicinalis, Kioto, 1919, 3, 31-48). The substantia propria of the 

 conjunctiva consists of a layer of connective-tissue containing fairly 

 numerous histiocytes of Kiyona, and smaller numbers of Marschalkos' 

 plasma cells and lymphocytes — contrary, therefore, to the wide-spread 

 assumption that the Tunica propria shows no adenoid condition. 



Lymph-nodes are absent from the normal conjunctiva ; they are pro- 

 duced when the tissues react against external irritation of different 

 duration and vigour. Only two other points come under consideration 

 in the formation of follicles in the conjunctiva. These are general 

 bodily health and a local disturbance of the tissue. These two points 

 depend firstly on age, and secondly on the anatomical structure of the 

 conjunctival parts. Now and then variation in the cell-abundance of 

 the sub-epithelial tissue and the form of the epithelial cells (cylin- 

 drical or flat) are specially emphasized. 



In trachoma early luxuriance of fibroblast occurs, without the forma- 

 tion of lymph-nodes or any increase of histiocytes, lymphocytes, or 

 plasma cells, so that a peculiar granulated tissue is formed in the sub- 

 epithelial layer, making the trachoma a kind of chronic granular inflam- 

 mation. Excessive granulation and the formation of lymph-nodes are 

 important in the pathology of trachoma, as they represent the reaction 

 product of the tissues against the trachoma virus. Granulation always 

 occurs in the scars caused by trachoma, whereas the follicle may be 

 missing if the local tissue-arrangement be imperfect — e.g. in conjunctiva 

 bulba and in pannus — hence the latter formation is less important than 

 the former. The question of the occurrence of follicles in pannus has 

 previously been answered in the affirmative. This is incorrect, however, 

 as is also the assertion that the trachoma process alone produces follicles. 

 Their scarcity is another point against it. Only an occasional con- 

 genital anatomical variation in the limbus is favourable to the formation 

 of follicles, a variation sometimes marked by an excess of cylindrical 

 cells in the epithelial layer. J. E. 



Nishikawa, Y. — " Zur vergleichenden pathologischen Morphologic 

 der chronischen Miltztumoren " (Mitteilungen aus der Medizinischen 

 Fakultat der Kaiserlichen Universitat zu Tokyo, 1919, 21, 1-215, with 

 bibliography). The author records anatomical, micrometrical, and com- 

 parative histological experiments on seventy-seven different kinds of 



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