1897 THE MICROSCOPE. 71 
Nine times out of ten if the insect is in the right 
condition, that is, has remained the right length of time 
in the potash, the contents of the abdomen which has 
been reduced by its action, begin to flow out through the 
anal orifice in the form of a brownish semi-liquid, and 
which disengages itself immediately when water is ap- 
plied. Inthe proportion that the abdomen empties itself 
increase the pressure towards the extremity. If there 
is a resistance it proves that one of the internal parts, 
probably the stomach, has been imperfectly dissolved and 
obstructed the anus, thus preventing the discharge. In. 
that case take a needle more or less fine according to the 
size of the insect and while continuing the pressure 
with the right hand, with the left carefully introduce the 
needle into the orifice, which, thus opened and enlarged 
will allow the remainder to pass out. 
The abdomen being very nearly empty, we will proceed 
to the head; there itis very necessary to have the pres- 
sure light and sure, for the work must be done with great 
precaution lest the delicate pieces of the cheeks be mis- 
‘placed or torn. 
The head being empty, hold the insect with the finger, 
while you take away the first water and replace it by an- 
other, in which, repeat the same process as before, adding 
the pressure of the legs, which should be from the tarsus 
towards the thorax. 
This operation ought to be repeated several times un- 
‘til there isnota particle of matter remaining in the in- 
terior of the subject. Then replace the distilled water by 
water to which has been added a small quantity of acetic 
acid. Now allow the insect to float upon a slide and 
after having expelled all the water arrange the different 
partsas naturally as possible, cover witha _ second 
slide, which should | be secured to the first by a thread, 
giving as much pressure as possible. Then place the 
whole in a bottle of 90 per cent aleohol for twelve hours. 
