PROGKESS OF MICROSCOPICAL SCIENCE. 27 



tlii'ough tlicm, and is deposited in the tissues iu the form of small 

 round cloudy patches. The evidence of the identity of the stomata 

 brought to view by means of cinnabar with those rendered apparent 

 by means of silver nitrate is obtained by their peculiar grouping in 

 the lymphatics of the frog's tongue ; and, secondly, by the subsequent 

 injection of silver nitrate into the same vessels. The injection of 

 cinnabar causes very little disturbance of the circulation. If a lively 

 exodus of the white corpuscles from the blood-vessels be produced by 

 making an abrasion of the surface, the migrating cells quickly make 

 their appearance in the stomata of the lymphatics marked out by the 

 cinnabar. They then take up the particles of cinnabar into their 

 interior, which causes them to lose their activity and accumulate in 

 the stomata. They immediately apjiear in the form of caiiliflower- 

 like excrescences projected on the inside of the lymphatics, which break 

 up into thin constituents — cinnabar-holding cells. These are seen in 

 motion in the lymphatics, and may be traced thence into the cervical 

 lymphatics and into the blood. In these researches a remarkable 

 uniformity in the track pursued by the white corpuscles was observed. 

 They then pass from the vessels into the tissue by a series of sharp 

 zigzag movements, and all travel at about the same rate. 



The Mamification of Sphacelarioe was also explained at the Wies- 

 baden meeting by Herr Pringsheim. According to Herr Magnus, 

 who made some remarks on this communication, there were two 

 modes in which it takes place. In the one the new shoot is formed 

 by an oblique partition cutting off a segment from the youngest cell 

 of the part about to branch. The segment eventually pushed the 

 weaker cell from which it was derived to one side, and a sympodial 

 ramification resulted (Stypocttidon). In the other mode a lateral shoot 

 is formed by a bulging out from a cortical cell (Sphacelaria), which 

 bulging out subsequently developed into a branch. 



The Slrncture of the Lamprey's Eye has been investigated lately by 

 Herr Langerhaus. The globe of the eye in this animal is peculiar in 

 being destitute of any sclerotic coat, and the choroid is directly con- 

 tinuous with the membrana descemetii. In ammocaetes the latter 

 membrane is very strongly develojjed, and completely fills the anterior 

 chamber. The iris is simply a continuation of the retina, which is 

 attached to the choroid by a thin layer of connective tissue. As Max 

 Schultze has shown, several layers are present in the retina. Inside 

 the external granule layer is found the ganglionic layer, in which a 

 double row of large ganglion cells are separated by a layer of fibres. 

 Within the ganglion layer lie the internal granule layer, the optic- 

 fibre layer, the granulosa, and limitans interna. Processes are given 

 off from the external ganglion layer which j^enetrate the lamina granu- 

 losa externa. The granules of the rods and cones dilate to form cup- 

 like bodies, which likewise stand in connection with the granulosa 

 externa ; and these cuj)s are situated, like Hauben (?), upon the pro- 

 cesses of the ganglion cells. Thus it is rendered highly probable that 

 there is a direct connection between the connective-tissue cups and 

 membranes of the granules and the connective tissue of the granulosa 



