PROGRESS OF MICROSCOPICAL SCIENCE. 
43 
plane or side of a muscle ; the valved efferents are found on the other 
side, as, for example, in the case of the diaphragm, transversal] s 
abdominis, and triangularis sterni muscles. In connection with this, 
they have discovered a dense plexus of valved vessels on the anterior 
surface of the abdominal wall, corresponding to that on the pleural 
surface of the diaphragm. Upon the lymphatics of muscle they find 
the peculiar serous cells first described by Ludwig and Schweigger- 
Seidel, whose views they fully confirm, in opposition to those expressed 
by Ranvier. They deny the existence of stomata in the Mammalia, 
but admit it in the case of frogs ; and as the peritoneum of the latter 
is lined by crenated lymphatic endothelium, they admit its connection 
with the lymphatic system ; but, on account of the absence of the 
latter endothelium as well as stomata from the serous cavities of 
mammals, they deny any connection between these and the lymphatics. 
While describing the structure of basement membrane, they discuss 
the facts adduced by Klein and Debove as bearing on the question of 
absorption, and give their own views on this question. They hold that 
the lower surface of the diaphragm is an exuding one, and only an 
absorbent one when all the natural conditions are reversed. They 
describe the minute anatomy of the lymphatics of the intestine, and 
show that it is the glandular structures, and not the muscles of the 
wall, that regulate the amount of these vessels. They also trace com- 
plete identity between these and the lymphatics of striated muscle. 
In either case they figure the connective-tissue cavities as forming the 
radicles of the lymphatics, but hold that these are not the only 
lymphatic afferents, nor that that is their only function. To prove 
this, they discuss the nature of these cavities, as they have discovered 
them in tendon and other gelatinous structures in different classes of 
animals to be of the same structure as in the cornea. Unlike man, 
the small mammals have no special vascular or lymphatic vessels in 
the peritoneal tissue, being dependent on the muscles below for those 
structures. The authors finish by entering upon a minute description 
of the apparatus employed by them, and offer a series of about sixty 
camera-lucida drawings of preparations in their possession in illustra- 
tion of their researches. 
How are Giant-cells developed. — Dr. Giovanni Weiss* says that 
giant-cells are formed by the melting together of many smaller cells ; 
these smaller cells are granulation cells. Giant-cells form also in 
connective tissue, and around blood-vessels ; but, even though under 
the most favourable conditions for existence, they invariably undergo 
fatty degenerative metamorphosis. 
Is there a difference between the Ova of Man and higher Mammalia ? 
— In a critique of a somewhat bitter kind, of Haeckel’s work in the 
‘American Naturalist’ (June 1877), the writer says: “Professor 
Bischoff | directly contradicts Haeckel’s assertion that we cannot 
discover, even with the aid of the best microscope with the highest 
* Virchow’s ‘ Arehiv,’ Oct. 1876. 
t ‘ Sitztun. math, pliys. Classe dcr k. b. Akad. der Wiss.’ Munchen. 1876. 
Heft i. p. 1. 
