4.20 
first described in conjunction with Dr. Burdon-Sanderson 
(see this Journal, October, 1870). He has now, with the 
help of Geltowsky, introduced some improvements. One of 
these consists in drawing out from the guinea pig’s abdomen 
the omentum alone without the stomach. Other details are 
given respecting the method of keeping the apparatus at a 
constant temperature, which could not be rendered intelli- 
gible without figures. 
Formation of Blood-vessels—Arnold (Virchow’s ‘ Archiv 
fiir Pathologische Anatomie,’ vol. lili, p. 70) has observed 
the development of capillary blood-vessels in the restoration 
of the tail of the tadpole when purposely cut off. Some new 
growth was seen a single day after the operation, and in two 
or three days they became suitable objects for examination. 
On the capillary vessels of the growing part were seen proto- 
plasmie duds of triangular form usually unprovided with 
nuclei, which tapered away into a row of fine granules, and 
were constantly lengthening. They sometimes formed the 
extremity of a vessel, and were sometimes situated laterally. 
Beside the buds were seen also a number of protoplasmic 
threads, starting either from the wall or the termination of a 
vessel, and becoming gradually prolonged. They varied 
much in thickness, and were sometimes hollowed out for a 
little distance, the cavity containing blood-corpuscles, and 
communicating with adjacent vessels. These threads always 
tended to form curves returning towards the body. 
Another form of protoplasmic structures were arches, 
stretched from one vessel to another ; some were thread-like 
in appearance, some solid cords of protoplasm, others already 
partly tunnelled; they sometimes contained nuclei, sometimes 
none. These three forms of structure were all seen by actual 
observation to originate in buds from the walls of capillary 
vessels, either complete or in process of formation ; and by 
observation from hour to hour the formation of the rudimen- 
tary vessels as protoplasmic cords and their subsequent 
hollowing out were traced. A number of figures illustrate 
successive stages in the formation of the same vessel as seen 
at intervals. The complete formation of an average capillary 
occupied ten or twelve hours. These observations agree in 
the main with those of Billroth on the same object; and 
with those of Stricker and Golubew on the normal develop- 
ment of the tadpole’s tail. Further observations on the same 
process in other organs are promised. 
Schultze’s ‘Archiv,’ vol. vii, Heft 3, contains the following 
papers: 
1. Ermer describes the terminations of nerves in the 
