59 
On Conjoined Epithelium. By S. Martyn. 
or turnip, and tie with a string. Cuts may be made along the mid- 
rib, or across it, including a portion of leaf on either side, or through 
several veins. Fine shavings of wood may be used, or pieces rubbed 
down on hones. 
Sections of leaves may be decoloured for staining by placing for 
some time in alcohol ; but I would recommend the use of Labar- 
raque’s solution of chlorinated soda, for twelve or twenty hours after 
the alcohol. Especially do I recommend the Labarraque for all 
kinds of wood. In twelve hours wood is generally bleached ; too 
long a residence in it will, however, often cause it to fall in pieces. 
After removing from the soda, wash through a period of twelve 
or eighteen hours in half-a-dozen waters, the third of which may 
be acidulated with about ten drops of nitric acid to the ounce, which 
acid must be washed out. Next put in alcohol, in which sections 
and also leaves may be kept indefinitely, ready for dyeing. 
Before closing this I would add a few suggestions concerning 
leaves not contained in my January article. 
Magenta, when used for them, should be of the strength of one- 
eighth or one-quarter of a grain to the ounce of alcohol, and purples 
and iodine-green two or three times as strong. These anilines are 
inferior to the blue in bringing out all the anatomical parts of a 
leaf, including the beautiful crystals so often met with. On re- 
moval from the dye, leaves should be thoroughly brushed with 
camel-hair pencils. 
One week, instead of forty-eight hours, is frequently required to 
effect the decolouration of large leaves in chlorinated' soda, even 
when they are cut into several pieces, which is advisable. 
Mr. L. R. Peet, of Baltimore, whose stainings in aniline are 
unsurpassed for beauty, thinks better results are attained by com- 
mencing with a weak dye, say from one-twentieth to one-twelfth of 
a grain, and slowly increasing the strength of the dye, at intervals 
of from one to three hours, until the required hue is obtained. 
This process certainly guards against too deep staining, and may 
give a finer tone to leaves under the glass. 
VI. — On Conjoined Epithelium. By S. Martyn, M.D., F.R.C.P., 
Lecturer on Medicine and Pathological Anatomy, Bristol 
Medical School. 
Plate CXII. 
It does not appear that much attention has been given by English 
observers to the so-called “ prickle and ridge ” cells ( Stachel - und 
Rijf-zellen). At all events, they have scarcely found their way into 
our most recent books on pathology; while the drawing in our 
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