610 SUMMARY OF CURRENT RESEARCHES RELATING TO 



It is not something hard and fast, but depends on the presence of two 

 physically different substances in the cytoplasm. 



Chondriosomes are present in all conditions of the cell, and they 

 share in differentiating the derivatives of the cytoplasm. They are to 

 be regarded as a characteristic component of the cytoplasm, and pro- 

 bably of a fatty nature. They are not to be identified with extra-nuclear 

 chromatin nor regarded as structural elements of the cell. They are 

 effective substances which share in differentiation when the chromatin 

 induces formative processes. 



Path of Hypophysis-secretion.* — L. Edinger has shown that the 

 secretion of the hypophysis passes from the gland-cells into pericellular 

 spaces, and thence by perivascular lymph-channels into the mass of the 

 brain. This explains why compression of the stalk has the same effect 

 as removing the whole organ. It may be that the secretion operates 

 especially through the sympathetic system, whose cerebral beginnings lie 

 near the region where the hypophysis enters the brain. 



Conjunctival Epithelium in Man. — Hans Yirchow has made a 

 thorough histological study of the conjunctival epithelium in man, dis- 

 tinguishing for instance the varying proportions of mucus-cells and 

 epithelial-cells. He describes no fewer than eleven figures of different 

 areas, all showing something distinctive in the structure of the con- 

 junctiva. 



Nuclear Budding in Corneous Epithelium.^ — Christian Ditlevsen 

 describes a peculiar process of nuclear budding which occurs in the strati- 

 fied corneous epithelium of the oesophagus and tongue in the guinea-pig. 



Retina of Birds. § — Gustav Fritsch has made a comparative study of 

 the retina of various birds, discussing in particular the area of clear 

 vision. The high degree of visual acuteness in the bird's eye is essen- 

 tially due to the delicacy and dense arrangement of the elements in the 

 restricted centre of the fovea. 



Grouping of Nerve-cells in Spinal Cord of Tench. || — L. Jacobsohn 

 makes a contribution to the topography of the nerve-cells in the spinal 

 cord of Tinea vulgaris, comparing it with that observed in man. He is 

 a strong upholder of heterogeneity of the nerve-elements, whether con- 

 sidered physiologically or histologically. 



The tench's spinal cord agrees with man's in showing (1) the same 

 large polygonal cells, rich in chromatin, in the ventral region of the 

 grey substance ; (2) the minute cells in the dorsal portion of the grey 

 substance ; and (3) the reticularis or " Strang "-cells. 



Peculiar to the tench's spinal cord are (1) the giant-cells in the most 

 posterior part of the cord ; (2) the rather large cells which occur some- 



* Arch. Mikr. Anat., lxxviii. (1911) Festschrift Waldeyer, pp. 496-505 (1 pi. 

 and 3 figs.). 



t Arch. Mikr. Anat., lxxviii. (1911) Festschrift Waldeyer, pp. 565-617 (2 pis. 

 and 2 figs.). 



% Anat. Anzeig., xxxviii. (1911) pp. 208-17 (10 figs.). 



§ Arch. Mikr. Anat., lxxviii. (1911) Festschrift Waldever, pp, 245-70 (4 pis. ). 



|| Arch. Mikr. Anat., lxxviii. (1911) Festschrift Waldeyer, pp. 506-28 (9 figs.). 



