ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 63 
•epithelium, Flemming has been led to believe, in the meantime, that 21 
is the normal number. 
Epithelium and Reticular Tissue.* * * § — M. Ed. Retterer has for many 
years made a special study of these tissues. Among his general conclu- 
sions we note the following : — (1) the existence of a basilar layer of 
elements with homogeneous protoplasm, opaque and coalescent, charac- 
terising epithelia in the stage of growth. (2) The homogeneous proto- 
plasm of this basilar layer elaborates a reticulum from which there 
arises the polyhedric epithelium du sabot or closed amygdaloid follicles. 
(3) The closed amygdaloid follicles and the interfollicular bridges arise 
entirely from epithelial buds of the pharyngeal mucosa. (4) Each 
closed follicle has three stages, epithelial, reticular, and fibrous. 
(5) The epithelium of the primitive invaginations, which persists in 
part in the adult in the lining of the amygdaloid crypts, is transformed 
in part into reticular tissue by a process analogous to that which occurs 
in the transformation of the closed epithelial follicle into reticular 
tissue. 
Heart Muscle-Cells.| — Mr. J. B. MacCallum describes the structure 
of the heart muscle-cells in man, dog, cat, pig, rabbit, and mouse, and 
their development in the pig. “ It is to be emphasised that in the pro- 
toplasm of the adult heart muscle-cell there are columns of fibrils which 
run longitudinally, surrounded by sarcoplasm, in such a way that each 
bundle is surrounded by a varying number of small sarcoplasmic discs, 
the horizontal separating partitions of which are continuous with 
Krause’s line on the fibril bundles.” In pig embryos there is a definite 
developmental sequence formed by the following five stages : (1) cells 
with a simple irregular network ; (2) cells with a regular network con- 
sisting of large sarcoplasmic discs ; (3) cells in which the large sarco- 
plasmic discs have been broken up with the formation of the small 
sarcoplasmic discs ; (4) cells in which fibril bundles have formed at the 
junction of the small sarcoplasmic discs with one another ; (5) adult 
cells as described above. 
Appearance of Intercellular Bridges between Smooth Muscle- 
Cells. J — M. Charles Gamier has studied in particular the muscular 
sheath of the oesophagus in the Greek tortoise, and the retractors of the 
long horns in the edible snail. He has convinced himself that an ap- 
pearance of intercellular bridging is often due to the network of 
connective tissue which enters into very intimate relations with the 
muscle. 
Hypophysis in Health and Diseased— Dr. G. Wolff has made some 
observations on the minute structure of the human hypophysis, in the 
main confirming those of Lothringer and Rogowitsch. What we know 
may be briefly stated : — The hypophysis is a blood-gland, without duct, 
penetrated by a very thick network of blood-vessels with very thin 
walls. There are two kinds of cells, more and less susceptible to 
stains. The gland secretes a substance, colloid, which in its chemical 
* Journ. Auat. Physiol., xxxiii. (1S97) pp. 461-522 (2 pis.). 
t Anat. Anzeig., xiii. (1897) pp. 609-20 (10 figs.). 
1 Journ. Anat. Physiol., xxxiii. (1897) pp. 405-20 (1 pi.) 
§ Verb. Phys.-Med. Ges. Wurzburg, xxxi. (IS97) pp. 223-35. 
