'682 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Eye of Protopterus annectens.* — Hosch gives some notes on the 

 structure of the eye in Protopterus, and discusses the phylogenetic 

 significance of the* facts elucidated. He considers that, apart from the 

 cornea, which in Protopterus has special adaptive features, a genetic 

 origin of its important constituents from the fish eye is indicated ; at 

 the same time the eye of Protopterus agrees in all essential points with 

 that of the next higher vertebrates, the Urodeles. 



Lacteal Secretion."]" — Brouha reviews the various theories as to 

 the nature of the lacteal secretion. He has studied the process in the 

 mole, the bat, and the cat, and finds that there are two distinct phases : 

 (1) a brief necrobiotic process, which involves the partial sacrifice of the 

 body of the cell ; and (2) an uninterrupted merocrinal process, which goes 

 on through the whole secretory cycle. The former leads to the expul- 

 sion of a small portion of cytoplasm which breaks up, liberating its fatty 

 or nuclear contents. The purely secretory or merocrinal phase leads 

 slowly to the distension of the mammary acinus ; the epithelium is 

 reduced to a delicate limiting membrane, and fatty globules are con- 

 tinuously secreted into the alveolus, which is eventually evacuated. 



Human Anal Glands.} — J W. T. Walker has investigated in the 

 human foetus, the coccyx gland which is known in all individuals from 

 birth to the end of life. He found it clearly in the foetus. The 

 youngest case examined was in the sixth lunar month. The gland con- 

 sists essentially of specific cells, which surround twisted and much 

 dilated capillaries, the central blood spaces. These cells are grouped in 

 numerous masses, which are supported and held together by connective 

 tissue ; certain masses are in the form of little nodules detached from 

 the chief part of the gland. Whilst in the foetus the gland appears 

 only as a cell mass, interpenetrated by twisted capillaries ; post-fcetally 

 the connective tissue penetrates this mass, dividing it up into numerous 

 cell groups, and certain of the blood spaces disappear. The structure 

 points to a fitting into the blood circulation ; it effects a local slowing 

 down of the same, thereby bringing the blood into closer connection 

 with the gland-cells. An endothelial layer always separates the blood 

 from the gland-cells. The gland has no duct, and an internal secretion 

 may be regarded as its most important function. 



Glands of Frog's Skin.§ — J. Arnold makes some notes on the struc- 

 ture and secretion of the glands of the frog's skin. He has not been 

 able to settle the question as to whether there are one or more kinds 

 present ; mucus and granular glands have been regarded as modifications 

 of one and the same type. At any rate one form cannot change to the 

 other, and no mixed types were found such as have been described in 

 Triton. The significant point of the results is the observation that in 

 the granular and mucus glands the formation of secretion is effected by 

 the transformation of the plasmosomes of the cytoplasm into secretory 



granules. 



* Arch. Mikr. Anat., Bd. 64 (1904) pp. 99-110 (1 pi.). 

 f Anat. Anzeig.. xxvii. (1905) pp. 464-7. 

 % Arch. Mikr. Anat., Bd. 64 (1904) pp. 121-57 (1 pi.). 

 § Op. cit., Bd. 65 (1905) pp. 649-65(1 pi.). 



