PROGRESS OF MICROSCOPICAL SCIENCE. 261 



fibre, which appears like a veiu or cajiillary charged with nitrate of 

 silver. In frogs, the nervous trunks, from six to fifteen in number, 

 pass into the cornea at the level of the internal elastic coat, lose their 

 medullary sheath, and subdivide into numerous fibres, which become 

 interlaced, and form a plexus in the interior layers of the cornea. 

 This plexus gives origin to many other fibres, which spread out in the 

 anterior layers of the cornea, and give off branches at a right angle. 

 These branches in their tm-n subdivide in the same way, forming a 

 network of fibres through the whole thickness of the cornea. The axis 

 cylinders become separated from the primitive fibres, and pass in a 

 straight line to the cylindrical epithelium, among the layers of which 

 they follow a winding course as far as the last layer but one, where 

 they form an irregular network, which is best seen in sections made 

 parallel to the anterior surface of the cornea. The arrangement of 

 the nerves in the cornea of the rabbit differs from that in the frog, 

 both in direction and in mode of distribution. The nerves, sixteen to 

 twenty in number, penetrate the cornea towards the outer part, and 

 form a plexus. The fibrils which penetrate the epithelium jiroceed 

 from the fibres which pass obliquely outwards from the plexus. Be- 

 neath the epithelium the fibres are divided into tufts and fibrils, which 

 penetrate the epithelium, some directly, others after a short passage, 

 and form in the penultimate layer a very fine fibrillar network, with 

 narrow meshes. Some of the fibrils form loops in the deep epithelial 

 layers. In the dog, the nerve-trunks entering the cornea are smaller 

 but more numerous than in the rabbit, and are distributed nearly in 

 the same manner. Some of the fibres pass directly to the under sur- 

 face of the epithelium, where they divide into numerous primitive 

 fibrils, which run parallel to the anterior sui-face of the cornea. From 

 these, other finer fibres are given off, which, having reached the last 

 layer but one of the epithelium, form the network which has been 

 already described. Sig. Durante did not find nerve-cells or corpuscles 

 among the fibres, nor any termination of the nerves in cells. 



The Intracellular Development of Blood Corpuscles in Mammals. — 

 At the meeting of the Eoyal Society, March 19th, Mr. E. A. Schjifer 

 communicated a very valuable paper on this subject. He says that if 

 the subcutaneous connective tissue of the new-born white rat is 

 examined under the microscope in an indifferent fluid, it is found to 

 consist chiefly of an almost homogeneous hyaline ground-substance, 

 which is traversed by a few wavy fibres, and has a considerable number 

 of exceedingly delicate, more or less flattened cells scattered through- 

 out the tissue. The cells here spoken of arc of course the connective- 

 tissue corpuscles. They are not much branched as a rule (at any rate 

 their branches do not extend far from the body of the corpuscle), and 

 they are mainly distinguished by the extraordinary amount of vacuola- 

 tion which they exhibit— by which is meant the formation within the 

 protoplasm of minute clear spherules, less refractive than that sub- 

 stance, and probably, therefore, spaces in it containing a watery fluid. 

 The nuclei, of which there is generally not more than one in each cell, 

 are frequently obscured by the vacu(des, but, when visible, are seen to 

 be round or oval in shape and beautifully clear and homogeneous ; 



