380 SUMMARY OF CURRENT RESEARCHES RELATING TO 



to be migrant cells of a leucocytic character, but they are almost 

 certainly of epithelial origin. Transitional forms are described. 



Medullary Endothelium.* — Hans Brass has studied the deposition 

 of pigment in the capillary endothelium of the medulla. The endo- 

 thelial cells are able by phagocytosis to ingest minute solid granules, 

 but not bacteria. In contrast to most vascular endothelial cells, they 

 take up and retain carmin particles injected into the blood. In the 

 rabbit, in normal conditions they are found to contain a yellowish- 

 brown pigment, which colours the capillary wall. This pigment is 

 modified haemoglobin, set free by the destruction of red blood-corpuscles, 

 but it gives no iron reaction. Thus, besides having a slight phagocytic 

 capacity, the cells have a synthetic power, shown in their assumption of 

 dissolved material in the blood and deposition of this in granular 

 form. In the dog the pigment-bearing cells are phagocytic more 

 markedly : theylingest erythrocytes and destroy them within themselves. 

 The pigment which the endothelial cells of the rabbit retain is re- 

 turned eventually to the blood-forming elements of the osseous medulla, 

 and doubtless utilized again in the formation of fresh erythrocytes. 



Rupture of Heart-muscle-fibres. f — H. E. Jordan and James Bardin 

 have studied the relation of the intercalated disks to the so-called seg- 

 mentation and fragmentation of heart-muscle. They find that rupture 

 of cardiac muscle-fibres always occurs in relation to the intercalated 

 disks, that these cannot be interpreted as intercellular structures, and 

 that, therefore, " segmentation " and " fragmentation " are not to be 

 distinguished anatomically as ruptures occurring in the intercellular 

 and intracellular portions respectively of the heart-muscle. As the 

 heart-muscle apparently possesses a syncytial structure, and as rupture 

 of the fibres always occurs in relation to a single structure (i.e. the 

 intercalated disks), '' segmentation " and "fragmentation " are probably 

 the same process, exhibited in different degrees of severity. 



Chondriosomes of Secretory Cells. J — G. Levi has studied these in 

 newts in particular, and finds that if they exhibit changes during the 

 phase of active secretion these are wholly of a passive sort. No ma- 

 terial continuity was demonstrable between chondrioconts and the 

 products of metabolism. The author is convinced that in sex-cells, 

 embryonic cells, and somatic cells of the adult, the chondriosomes are 

 permanent cellular organs, not susceptible of metamorphosis. 



Intertubular Cell-mass of the Pancreas. § — Gakutaro Osawa calls 

 attention to the fact that in Lmumda yokohamse and Verasper variegatus 

 the cell-mass of Langerhans is free from the pancreas. He would call 

 it the organ of Langerhans as opposed to " islands " or secondary cell- 

 groups which are embedded in the pancreas. A similarly independent 

 organ of Langerhans has been reported by other investigators, e.g. by 

 Eennie in Lophius. 



* Arch. Mikr. Anat., Ixxxii. (1912) Abt. l,pp. 61-78 (1 pL). 

 t Anat. Anzeig., xliii. (1913) pp. 612-17 (7 figs.) 

 t Anat. Anzeig., xlii. (1912) pp. 576-92 (12 figs.). 

 § Anat. Anzeig., xliii. (1913) pp. 476-9 (1 fig.). 



