708 SUMMARY OF CURRENT RESEARCHES RELATING TO 



vicinity of the endothelial walls in the human hypophysis, which have 

 a strong resemblance to erythroblasts, especially to those of the embry- 

 onic liver. 



Red Blood Corpuscles of Mammals.* — E. Retterer and A. Lelievre 

 have studied the development of red blood corpuscles (in connexion 

 with the hyoidean apparatus in embryos of dog and cat), and they 

 come to the conclusion that the corpuscle in the adult is only the 

 nucleus, the cytoplasm having become fluid. In oviparous Vertebrates, 

 in embryo Mammals, and in anaemic Mammals, the red blood corpuscle 

 is a cell ; in a healthy adult Mammal it is a nucleus. 



Life of Isolated Cells.j — J. Jolly has observed cell-division in the 

 red blood corpuscles of the newt in blood which had been isolated for 

 15 days. In a small quantity of blood taken directly from the heart 

 and kept for 4| months in a tube placed in ice, the leucocytes were still 

 alive. With the blood of frog and Mammal, prolonged survival in 

 vitro was also observed, but the best temperature in these cases seems 

 to be a little above zero. 



Structure of Sclerotic! — J. Chatin points out that while the 

 sclerotic of Mammals generally consists of more or less dense connec- 

 tive tissue, there is great diversity in other Vertebrates. It may show 

 chondrification, or even ossification. In PlatydactyJus muralis and 

 Gymnodactylus scaler there is typical hyaline cartilage. In Birds there 

 are well-known sclerotic ossicles. It is interesting to find fibrous tissue, 

 cartilaginous tissue, and bony tissue — a related series — occurring in 

 different types in the same situation. 



Chordoid Tissue.§ — Josef Schaffer discusses the nature of the tissue 

 composing the notochord. It is not to be referred to cartilage, nor to 

 epithelial tissue. It rather represents a supporting substance of wide 

 occurrence and manifold forms, which may be regarded as the phyletic 

 predecessor of cartilage. It may be called vesicular supporting tissue 

 of the chordoid type, or, more briefly, chordoid supporting tissue. It 

 includes diffuse and compact forms, and the general characteristics are 

 the following : — 1. It is composed of vesicular or spherical cells, whose 

 form and elasticity are determined by the turgor-pressure of the enclosed 

 fluid. 2. The cells have a differentiated peripheral membrane, which 

 has increased elastic resistance as the turgor-pressure decreases. 3. 

 The cells can be readily isolated, for there is no intercellular substance. 



Structure of Bone in Sunfish.|| — M. Nowikoff points out that the 

 five different kinds of bone which Kolliker recognized in fishes do not 

 exhaust the manifold diversity. The bones of Orthayoriscus mola, with 

 their characteristic chambered meshwork, are very remarkable. Two 

 kinds of bone-substance may be distinguished. The first forms the 

 walls of the chambers, and exhibits a large number of Sharpey's fibres. 



* C.R. Soc. Biol. Pari?, lxix. (1910) pp. 19-22. 

 t Tom. cit., pp. 86-8 (5 figs.). 

 X Comptes Rendus, cli. (1910) pp. 185-6. 

 § Anat. Anzeig.. xxxvii. (1910) pp. 231-9. 

 •II Tom. cit., 98-106 (6 figs.). 



