QuEKETT on the Raphides of Cactus enneagonus. 
25 
material in the vegetable or animal kingdom, except in the 
crystalline state, without the existence of an organic basis. 
Since the above was written, my friend Dr. Lionel Beale 
has been kind enough to examine the raphides in question, 
and the following is his report on the subject. 
" A few of the white globular crystalline masses were 
treated with boiling distilled water, and the aqueous solution, 
after being filtered, was evaporated to a small bulk. Upon 
examining the residue by the microscope, numerous small 
colourless crystals, in the form of obtuse rhomboids, were 
observed. The residual solution was found to give precipi- 
tates insoluble in strong nitric acid, with solutions of nitrate 
of barytes and nitrate of silver, proving the presence of 
chlorine and sulphuric acid. Oxalate of ammonia gave a pre- 
cipitate insoluble in acetic acid, but soluble in strong nitric 
acid, showing the presence of lime. 
" Hence boiling distilled water extracted a small quantity 
of soluble matter, which contained lime, chlorine, and sul- 
phuric acid, probably in the form of sulphate of lime and 
chloride of sodium. 
" Acetic Acid. — The crystalline masses were not affected by 
boiling acetic acid. 
" Potash. — No observable action was produced by boiling a 
few of the masses in solution of caustic potash. 
" Nitric Acid. — Upon the addition of strong nitric acid, 
effervescence occurred with some few of the bodies as they 
dissolved, but upon the majority this re-agent exerted little 
action in the cold. When the mixture was boiled, complete 
solution immediately took place. 
" The acid solution was evaporated to dryness ; the dry 
residue was boiled in distilled water, and the filtered solution^ 
after concentration, was allowed to remain in a still place for 
some time. Upon examining the residue with the microscope 
numerous well-formed octohedra of oxalate of lime were ob- 
served. 
" Another portion of the original matter was incinerated : — 
the masses still retained their globular form, but became black, 
and the products of combustion burnt with a blue lambent 
flame. After exposure to a dull red heat for three or four 
hours, the crystals were perfectly decarbonized, and by the 
unaided eye could scarcely be distinguished from those which 
had not been incinerated. Upon microscopical examination, 
however, the crystalline fragments of which the crystalline 
masses were composed, were found to have acquired a dark 
granular uneven surface, and the sharpness of outline had been 
