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 PEOGKESS OF MICKOSCOPICAL SCIENCE. 



Tlie Placental Circulation has been again investigated ; this time by 

 M. Delove, who read a paper before the French Biological Society. 

 Whatever value may be attached to his researches, the following facts 

 are of interest : — (1) An injection made by the circular sinus penetrates 

 the whole of the placenta, and the same thing takes place if an in- 

 jection be made by the umbilical vessels. ('2) The placenta of the 

 still-born infant, of which the blood has lost the coloui'ing matter, 

 shows recent clots in its interior. (3) All the collected sections of the 

 placenta show villosities in contact with blood corpuscles. (4) The 

 presence of the vascular epithelium in the placental sinuses is a fui'ther 

 proof that blood passes through them. 



A Nervous System in the Actinia. — Professor M. Duncan, F.R.S., 

 has been making some very valuable researches on this point, and 

 has published the results, with a couple of excellent plates, in a late 

 number of the ' Proceedings of the Eoyal Society.' We hope to lay 

 both the author's investigations and his plates before our readers, in 

 an early number of this Journal. 



The Ovarian Egg and Early Development of Loligo. — Under the 

 title of " Contributions to the Developmental History of the Mollusca," 

 Mr..E. Eay Lankester, M.A., has read a very valuable essay before the 

 Eoyal Society, which will be published fully, with illustrations, in the 

 ' Transactions.' The following is a short account of the chief points of 

 interest in the section devoted to Loligo : — (1) The explanation of the 

 basketwork structure of the surface of the ovarian egg by the plication 

 of the inner egg-capsule. (2) The increase of the yelk by the incep- 

 tion of cells proliferated from the inner egg-capsule. (3) The homo- 

 geneous condition of the egg at fertilization. (4) The limitation of 

 yelk-cleavage to the cleavage-jiatch. (5) The occurrence of inde- 

 pendently-formed corpuscles (the autoplasts) which take part in the 

 formation of the blastoderm. (6) The primitive eye-chamber, formed 

 by the rising up of an oval wall and its growing together so as to 

 form a roof to the chamber. (7) The origin of the otocysts by in- 

 vagination. (8) The rhythmic contractility of a part of the wall of 

 the yelk-sac. (9) The disappearance of the primitive mouth, and the 

 development of a secondary mouth. (10) The development of a pair 

 of large nerve-ganglia by invagination of the epiblast immediately 

 below the primitive eye-chambers. 



How the Nerves end in the Cornea. — Dr. Henry gives an account in 

 the ' Medical Eecord ' of a recent paper by Signor Durante, who has 

 made observations on the subject at Eome. This observer states, that 

 hy soaking the cornea of batrachians, rabbits, and dogs, in solution of 

 chloride of gold, and keeping them at a temperature of 88° Fahr., he 

 was, at the end of four days, enabled to see a very distinct network of 

 nerves. When a combination of nitrate of silver and chloride of gold 

 is used, the intercellular substance is sometimes coloured ; not the 



