QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 181 



are, in fact, true nucleated cell-plates like those described by 

 Hoyer and Schweigger-Seidel from the cornea. For the 

 most part they have no processes. The size varies con- 

 siderably, but is generally greater in adult or old individuals 

 than in young ones. Cells from the tendons of the frog 

 measured "1 mm. long by '01 broad, and the nucleus "Oo 

 mm. by "007 mm. In the Achilles tendon or ligamentum 

 patellae of old men some remarkably long cells were found. 

 Oue cell measured '168 mm. long by '003 mm. wide, and its 

 nucleus "05 mm. by "0025. 



On the whole, Bizzozero concludes that the spaces are 

 occupied completely by fixed cells connected by anastomosing 

 processes. In the Italian version of his paper he states that 

 he has been quite unable to confirm the results of Rauvier. 

 Of other recent memoirs he takes no notice. 



Development of Vessels. — Klein has published (' Sitzungs- 

 berichte der Wiener Akad.,' 13d. Ixiii, Abtli. 2) an important 

 memoir on " The middle germinal layer and its relations to the 

 first blood-vessels ajid blood- corpuscles in the embryo of the 

 common fowl." The memoir consists of two parts. The first 

 part, after a long and elaborate historical introduction, treats 

 of the development of the middle layer in the germinal 

 membrane of the fowl's embryo ; while in the second is shown 

 how blood-vessels and blood-corpuscles are developed out of 

 special elements in this layer. 



If the germinal disk of unincubated eggs laid in spring 

 be divided into thin sections, it is easy to convince oneself 

 that the central part is in many respects different from the 

 periphery; that is, from those sections corresponding to the 

 area opaca ; the central part of the disk appears to consist 

 over a considerable area of two layers, which are at some 

 places separated by an interval, at others lie close together. 

 The cellular elements arranged like an epithelium in the 

 upper layer are cylindrical, finely granular, and distinctly 

 nucleated ; the less closely arranged and somewhat larger 

 cells of the lower layer are roundish and coarsely granular, 

 for which reason a nucleus can only rarely be seen in them. 

 In its peripheral parts the germinal disk is quite otherwise 

 constructed : the two layers are here so closely united that a 

 separation of the elements into groups is not conceivable ; 

 the cells are also actually larger, and hence the disk is 

 thicker at the periphery than in the centre ; it appears to be 

 made up of large globular bodies with distinct and brilliant 

 granules. 



Similar coarsely granular spherical elements which lie on 

 the floor of the segmental cavity, and are arranged together 



