748 
DE. J. S. BOWEEBANK ON THE ANATO]\IT 
since in the vegetable kingdom we nowhere meet with a substance in the slightest 
degree resembling fibroin.” 
From the general physiological characters of the skeletons of the Sertularian and 
other Zoophytes, I had long suspected that their component parts were identical, or very 
nearly so, with those of the skeletons of the Spongiadse, and I therefore applied to my 
friend Mr. Geoege Bowdlee Buckton to assist me in determining this point, and he 
very kindly undertook to make comparative qualitative analyses of two species of 
Zoophytes, Sertularia operculata and Flustra foliacea, with the fibres of Spongia offici- 
nalis and of raw silk, and 1 cannot do better than quote entire the report of the results of 
his examination : — 
“ I have examined the Zoophytes you sent me, and have compared their deportment 
under chemical agency, with that shown by white silk and the fibre of ordinary sponge. 
“ All the specimens were treated in a similar manner, being purified from foreign 
matter, as far as possible, by boiling for two hours in water, and subsequently for the 
same period in strong acetic acid. With the exception of Flustra, the substances exhi- 
bited by this treatment little change in their outward appearance. Carbonate of lime 
enters so largely into the composition of Flustra^ that its disintegration by acids ought 
to cause no surprise. 
“ From the results of the first seven experiments, which for convenience I have 
arranged in a Table (see next page), I conclude that all these bodies contain the same, 
or a very similar animal principle, which I suppose to be identical with Muldee’s fibroin. 
The varying colours of the precipitates from tannic acid and ammonia, I think are 
probably due to the traces of sesquioxide of iron present in the fibres, and the difference 
in shade is simply caused by the greater or less preponderance of that metal. 
“ Although I have not been able to obtain fibroin in a state of chemical purity, I 
would state that, to my knowledge, there is no vegetable principle which behaves itself 
towards reagents in a manner similar to that shown by the substance of silk, sponge, &c. 
“ Muldee and Ceookewit’s analyses show silk and sponge scarcely to differ in compo- 
sition. 
Eibroin from silk. 
Eibroin from sponges. 
Carbon 
48-5 
Carbon . . 
. . 46-5 to 48-5 
Hydrogen 
6-5 
Hydrogen 
. . 6-3 6-3 
Nitrogen 
17-3 
Nitrogen . 
. . 16-1 16-1 
Oxygen 
Oxygen 
Sulphur 
- 27-7 
Sulphur 
■ . . 31-1 29-1 
&c. &c. 
Phosphorus 
Iodine 
100-0 
100-0 100-0 
“ ScHLOSSBEEGEE has recently expressed his doubts of the identity of composition of 
