LIVERPOOL MEDICAL INSTITUTION. 417 
ments forming the “plexus” alluded to by Harvey and others, 
which, indeed, ultimately forms a very “‘jungle,’ the nature 
of which is very difficult to penetrate or follow out. None of 
these peculiarities seemed to have been investigated by Agardh 
or Harvey. But in brief and naturally scanty ‘ Minutes’ like 
these no justice could be done to so complicated structures, and 
Mr. Archer would have to defer to a more enlarged opportunity 
an effort to make up some description of them, and of the seeming 
mode of evolution of the system of ramification, the whole 
forming a subject which indeed seemed to grow as he proceeded 
in the investigation, and to take more time to endeavour to 
follow out than he had at first anticipated. 
MicroscoricaL SEecTION oF THE LivERPooL MEpICcAL 
; INsTITUTION, Sesston 1874—75. 
Tur first meeting of this section was held on the 16th October, 
1874, at which Dr. Caton described a new form of microscope 
which he had had prepared for physiological purposes. He re- 
marked that, as the methods of preserving and preparing tissues 
and organs for microscopical research were now nearly perfect, 
the aim of the physiologist was to examine tissues in the living 
state; but two great obstacles required to be overcome, viz., 
that, by the instruments at present in use, only mesentery and 
omentum could be examined, and, further, that great difficulty 
was experienced in preventing injury from evaporation and from 
loss of temperature. Having detailed fully Drs. Burdon Sander- 
son and Stricker’s “ warm stage,” the author proceeded to describe 
his new instrument. Dr. Caton cuts off the front half of the stage 
of his microscope, and places immediately under the objective a piece 
of concave glass heated by a warm chamber. On this glass plate 
the tissue to be examined is placed. To preserve the natural 
moisture of the tissue it is floated in a very weak solution of 
salt. The optical portion of the instrument is made movable, so 
that during focussing the object examined is not altered in its 
position. The. heating apparatus is a hollow brass box, having a 
thermometer attached, and, fixed to this box, are two india-rubber 
tubes, the one carrying water to, and the other from, the stage. 
The necessary heat is obtained by means of an iron tube heated 
in a gas flame, and communicating with the stage cavity. 
At the second meeting of the section, held on January 8th, 
1875, Dr. Davidson described the “ microscopical characters of 
the kidney in post-scarlatinal dropsy.”” Having referred to Prof. 
Klebs’s observation that this pathological process consisted in a 
proliferation of the epithelial cells in the Malpighian corpuscles, 
and that some of these cells became fatty while others desqua- 
