116 HERBERT E. DURHAM. 
the larger hemal spaces which exist on the surface of the 
organ, whereby they might get carried to other regions—an 
accident which would not be likely to occur in the close mesh- 
work of the deeper parts of the organ, spaces of which, though 
permeated by, are not distended with, hemal fluid. In the 
specimens examined cilia are not apparent in the pits. 
We may conclude, therefore, that there are no free com- 
munications between the coelom and the axial sinus in 
Echinus sphera and Spatangus purpureus, such as 
occur in Asthenosoma. 
V. Note on TECHNIQUE: A COMBINED METHOD FOR FIXING 
AND FLATTENING PARAFFIN SECTIONS. 
This method is a modification of one mentioned by Haiden- 
hain (No. 35), originally practised by Canini (‘ Arch. f. Anat. 
und Physiol.” 1883, p. 155), in which alcohol is used as a 
means of causing the sections to adhere to the slide. It was 
in performing the method that I contrived a modification, 
which I venture to think is an improvemement. 
The following is the routine :—The section or sections are 
placed upon either a dry slide or one moistened with ordinary 
methylated spirit diluted to 70 per cent. alcohol. The 
slide is then placed upon a horizontal metal plate which is 
kept warm ; its temperature should be only sufficient to soften 
and not completely melt the paraffin used ; another slide with 
a ribbon of useless sections of the same paraffin forms a good 
“thermoscope.” As soon as the slide has been placed on the 
warm plate more alcohol (70 per cent.) is run on by means of 
a pipette, the amount required being learnt by practice ; if the 
sections are small a small quantity will suffice, if they are 
large a greater quantity will be requisite. As the slide be- 
comes warm the paraffin softens, and any little wrinkles dis- 
appear, the sections floating flat on the top of the alcohol. 
When they all appear flat the excess of alcohol may be 
removed with a pipette. If too much alcohol has been added 
the ribbons tend to get seriously displaced ; they can, however, 
