PROGRESS OF MICROSCOPICAL SCIENCE. 81 



mentioned mass of opaque elements at the stage when the germ 

 vesicle was seen to consist of only one layer of cells, Weil takes it as 

 improbable that this mass of elements participates in the formation of 

 the area germinativa, and is therefore in agreement with the earlier 

 assertion of Bischoff and that of Bemak, and against the later assertion 

 of Bischoff and that of Coste. Weil does not give any explanation of 

 the spherical finely-granular bodies that are to be found between the 

 germ and the zona pellucida previously to, as well as in, the earlier 

 stages of the cleavage process. He does not think it necessary to 

 conclude that they stand in a relation to the germinal vesicle (viz. the 

 nucleus of the unfertilized germ), which, according to some authors, 

 leaves the germ before the cleavage process commences. The method 

 employed by Weil in his researches is as follows : — Within the first 

 twelve hours after littering, the female is coupled with the male ; from 

 twelve until about eighteen hours after coition, the oviduct and ovary 

 of one side are excised from the living animal, which is then allowed 

 to live, the wound being treated according to the ordinary rules ; the 

 other oviduct may be made use of at a later period. For observation 

 of the ovum from eighteen hours to seven days after coition, the 

 cornua uteri are excised. In the first instances the oviduct is freed 

 by the aid of forceps and scissors from the surrounding fat and peri- 

 toneum, and opened on a glass slide with fine scissors inch by inch. 

 Whether ova have left the ovary can easily be recognized by the 

 presence of blood-stained specks on the ovary — the openings of 

 ruptured Graafian follicles. The folds of the mucous membrane being 

 stretched with a pair of needles, ova can be discerned under a lens 

 as spherical bright bodies. 



The Nerves of the Cornea. — Dr. Woodward has, in the American 

 journal the ' Lens,' complimented Dr. E. Klein upon his paper in this 

 Journal. He says that the " London ' Monthly Microscopical Journal ' 

 for April, 1872, contains an admirable paper, by Dr. E. Klein, of the 

 Brown Institution, ' On the Finer Nerves of the Cornea,' which sub- 

 stantially corroborates Cohnheim's observations, while some new and 

 important points are added. This paper is illustrated by two admi- 

 rable plates, to the accuracy of which I bear my humble testimony. 

 The chief point of difference between Cohnheim and Klein is, that 

 while the former thinks the sensitive nerves of the cornea terminate 

 in various animals in the substance of the anterior layer of epithelium, 

 or on its surface, in free extremities, the latter holds that the peri- 

 pheral termination is a network. The difference of opinion appears 

 to result from the circumstance that Cohnheim used perpendicular, 

 Klein oblique sections. At the Museum both have been made, and 

 both correspond to the descriptions of the distinguished investigators 

 named. After careful comparison, I am disposed to approve the 

 modification of Cohnheim's views adopted by Klein as best covering 

 all the facts of the case." 



Dr. Beale's Theories from an American point of view. — Dr. Dan- 

 forth, who is pathologist to St. Luke's Hospital, Chicago, in a recent 

 paper says that to " Professor Lionel S. Beale, of London, the world 



