152 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mesenchyme. He therefore submits a case — the development of the 

 maxillary teeth in Acipenser ruthenus — where it seems quite clear that 

 the ectoderm gives origin to the mesenchyme. 



Deformity of Head in Abramis vimba.* — E. Leonhardt has studied 

 the peculiar deformity known as " Mopskopf ." It is known in carp, 

 pike, trout, salmon, bullhead, and other fishes. It appears to be induced 

 by a displacement of the embryo within the egg-envelope, in consequence 

 of which there is unequal pressure on the part of the envelope on the 

 body of the embryo. 



b. Histolog-y. 



Blood of the FowLj — W, Rosenthal has studied this with the 

 highest powers and with the ultra-microscope. The mature erythrocytes 

 consist of the nucleus ; the endosome, soluble in water, and containing 

 the haemoglobin ; and the envelope, insoluble in water. The envelope 

 is probably viscid ; it is limited externally by a precipitate-membrane. 

 From its substance extremely delicate smooth flexible tilaments may be 

 seen to arise, such as were seen also in the blood of the mouse. 



Alleged Artificial Cells. | — Gaston Bonnier points out that Leduc's 

 artificial cells correspond to the curious precipitates elaborately studied 

 by Traube from 1865 onwards, and to the arborescences described by 

 Pfeffer (1S77) and others. The form of the precipitate is a function 

 of the medium in which it develops and, to a certtiin extent, of the form 

 of the vessel containing the solution. There is nothing new in Leduc's 

 results except his assertion that his artificial cells — tubular metallic pre- 

 cipitates — have a cellular structure and most of the functions of life 

 except reproduction. 



Epithelial Corpuscles in Manimals.§ — J. Erdheim has studied the 

 glandulae parathyroidea?, or epithelial corpuscles, in the rat, rabbit, and 

 hedgehog, and finds that there is a normal occurrence of accessory epi- 

 thelial corpuscles — sometimes seven (rat), nine (rabbit), or five (hedge- 

 hog). 



"Minute Spaces" in the Body.|l— P. Schiefferdecker argues for the 

 probability of the existence of ultra-microscopic spaces in the tissues, 

 which, in spite of their minuteness, are of significance in the nourish- 

 ment of tissue. There are such spaces in connective, nerve, and bone 

 tissue. The author assumes a fluid stream carrying nutritive sub- 

 stances from the blood-vessels through these channels. 



Action of Anaesthetics on Living Tissue.lf — X. H. Alcock has 

 made numerous experiments on the action of anaesthetics on living 

 tissues. He finds that chloroform breaks down a semi-permeable 



* Zool. Anzeig., xxxi. (1906) pp. 53-60 (2 figs.), 

 t Biol. Centralbl., xxvi. (1906) pp. 697-720. 

 j Comptes Rendus, cxliv. (1907) pp. 55-8. 

 § Anat. Anzeig., xxix. (1906) pp. 609-23 (5 figs.). 

 II Arch. Milir. Anat., Ixix. (1906) pp. 439-55. 

 t Proc. Roy. Soc. London, Series B, Ixxviii. (1906) No. B 523, pp. 159-69 (5 figs.) 



