98 PROCEEDINGS OF SOCIETIES. 
were also enlarged. He had traced the epitheliomatous growth 
to the original ichthyotic patch. 
Dr. Goodhart, in reply, preferred retaining the term ichthyosis 
lingue as one well understood now. Had but once seen the 
“white cicatricial patch’ described by Mr. Fairlie Clarke; he did 
not think it cicatricial in character, for it could be scraped off, and 
suggested its being owing to some chemical change on the 
mucous surface. 1t was not the rule to find the “ bird’s nests” 
of epithelium in epithelioma of the tongue; but he had usually 
observed an abundant infiltration of small cells under the epithe- 
lium, as in ichthyosis lingue. The second cause for cancer 
following this disease, given by Mr. Fairlie Clarke, was useful in 
explaining those cases where the direct extension of the disease 
from the original patch could not be observed. He had never 
verified Mr. Needham’s observation of hypertrophied papille, 
though he had heard that condition described before. 
7 
Royat Mickoscortoat Socrery. 
May 6th, 1874. 
Suctorial Organs of the Blowfly—Dr. Anthony drew attention 
to the presence of certain “‘chitinous rings” or “arches” con- 
tained in a zigzag slit or furrow which passes down each of 
the pseudo-trachee, or quasi-tubes of the tongue. These rings 
keep the slit or furrow open, and were supposed to be concerned 
in suction. 
Silica Films artificially produced.—In a former communication 
Mr. H. J. Slack had described a variety of beaded patterns 
that could be obtained by making the artificial diatoms of Max 
Schultze. Silicic fluoride gas is allowed to come in contact 
in its nascent state with cotton filaments moistened with 
water ; the result is a deposition of silica in the shape of 
irregular vesicles, the walls of which exhibit beaded structures 
in definite patterns. If the gas is passed simply into water, 
the silica is deposited in amorphous particles, but by using 
a mixture of glycerine and water very delicate films are ob- 
tained which show a very complicated beaded structure: some 
have a striking though illusory resemblance to organic cell-forms, 
and even to bacteria and fungi. The size of the spherules is 
sob00 1 aosoo0 Of an inch. 
On the use of Black Shadow Markings and a Black Shadow 
Illuminator.—The intensity and clearness of black shadows as seen 
with the microscope was recommended by Dr. Royston Pigott asa 
test of the excellence of the instrument. Some observations made 
on the spherules of silica obtained by Mr. Slack’s process were 
described, and reference was made to the black shadow illuminator 
constructed by the author in 1864. 
