246 
NOTES AND MEMORANDA, 
easy enougli to prepare sections of the soft tissues after decalci- 
fication, and of the hard dried corallum by the old process of 
grinding, but the results thus obtained have then to be com- 
bined more or less by guess work. Dr. G. von Koch has lately 
sent me a series of microscopic sections of corals prepared by 
him by means of a method which he described in the ^ Zoolo- 
gischer Anzeiger,^ No. 2, 1878, S. 36. In these sections the 
hard and soft tissues are maintained in their exact relations to 
one another, and both are reduced to a sufficient thinness to 
exhibit their minute structure in all essential details. Amongst 
them, for example, is a complete section across a Caryophyllia, in 
which the arrangement of the mesenteries with regard to the 
septa is most fully and clearly exhibited. Dr. von Koch has 
described the results at which he has arrived by means of his 
method of section cutting, in a series of papers published in the 
‘ Morphologisches Jahrbuch,^ and elsewhere. His latest paper, 
which gives an account of some points in the structures of 
Caryophyllia, is contained in the ^ Morpbol. Jahrb.,^ Bd. v, S. 
316 Bemerkungen fiber das Skelett der Korallen^^). 
My object in writing this note is to testify to the great success 
of Dr. von KocKs method. It will yield valuable results not 
only in the case of corals, but also in all other problems of 
histology or minute anatomy in which the relations of hard and 
soft parts have to be determined. It^ might, perhaps, be em- 
ployed with advantage in the examination of the structure of 
Cortfis organ. Sections could thus be prepared of the undecal- 
cified cochlea in which the components of the organ of Corti 
would be seen in sitiiy and unaltered by the action of acids. 
Sections of injected bone, showing the relations of the blood- 
vessels to the Haversian system, could also thus be made. 
Sections across the arms of undecalcified Crinoids and Starfish, 
and many similar preparations, suggest themselves as likely to 
yield valuable results. Dr. von Koch^s method is described in 
full in the ‘ Zoologischer Anzeiger ^ in the notice quoted above. 
The hardened objects of which sections are to be cut are stained 
and treated with absolute alcohol, and then placed in a solution 
of gupa copal in chloroform. The objects are then slowly dried 
by means of artificial heat till they are stony hard. They are 
then cut into sections with a fine saw, and the sections are 
rubbed smooth on a bone on one side, then fastened to the slide 
with the copal solution, and ground down with a grindstone 
and hone on the other, just as in the case of ordinary sections of 
bones and teeth. — H. N. Moseley. 
