ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
473 
As to the structure of the free surfaces of cells, the striated marginal 
layer found in epithelial cells has often been regarded as cuticular in 
structure, but according to the author it is in origin and structure 
similar to typical intercellular connections, and is merely exposed by 
the death of the outer cell with which its intercellular bridges were 
once connected. The cilia of ciliated epithelial cells have already 
been homologised with the striated layer of non-ciliated cells, so that 
the possibility of comparing them with intercellular connections natur- 
ally follows from the above. It is of special importance to note that 
at their bases little swellings occur comparable to the swellings on the 
rods of the striated layer and to the similar structures on the inter- 
cellular bridges. The author believes that cilia are at least in part 
equivalent to the rods of the striated layer, and that this striated layer 
shows much resemblance to the intercellular structures. 
Mammalian Epidermis.* — Prof. L. Ranvier maintains that seven 
distinct layers should be recognised in the epidermis of man and 
mammals. Following the developmental order, he calls these stratum 
germinativum, filamentosum , granulosum, intermedium , lucidum, corneum , 
and disjunctum. Each has distinct physical characters and chemical 
reactions, and the limits are well defined. But it must not be supposed 
that these layers are formed by special elements. A cell originating 
in the s. germinativum changes its character and passes into the s.jila- 
mentosum , and so on, “ as if knowing what to do and doing it.” 
Ganglion- cells of Spinal Cord.j — Dr. Emil Holmgren publishes a 
preliminary note of his researches on this subject, confining himself to 
some conditions found in the rabbit and the frog. In the rabbit he has 
found a network of fine tubes ramifying through the cell, which he 
believes to be identical with the fibrillar network described by Golgi 
in the rabbit and the cat. He does not believe that these tubes carry 
blood, and has succeeded in demonstrating true intracellular capillaries 
in the same cells. The method employed was to fix in sublimate con- 
taining picric acid and to stain with toluidin-erythrosin. 
As to the ganglion-cells of the frog, serial sections seemed to cast 
light on the “microcentra” described by Lenhossek. They showed that 
the “ microcentra ” and the “ centrosphere ” are appearances presented 
by sections through a spiral figure imbedded in the cell-protoplasm. 
The spiral figure consists of coils certainly formed of differentiated 
cytoplasm, between which lie fibrils having the staining reactions of 
the capsular structure which surrounds the proximal part of the axial 
cylinder. By treating the ganglia with salicylic alcohol and staining 
with iron hematoxylin combined with acid fuchsin, orange, or rubin, 
it can be clearly shown that these fibrils are spirally coiled nerve-fibrils 
which penetrate into fhe cells. 
Neurites in the Central Nervous System.^; — Dr. Semi Meyer has 
used toluidin-blue instead of methylen-blue for the study of nerve-cells, 
and finds that although essentially similar in its action, it in some cases 
gives clearer figures. He has also used methylen-blue with Bethe’s 
* Comptes Rendus, cxxviii. (1899) pp. 67-70. 
t Anat. Anzeig., xvi. (1899) pp. 161-71 (11 figs.), 
t Arch. f. Mikr. Anal., liv. (1899) pp. 296-311 (1 pi.). 
