1142 General Notes. 
and many anura, a mixture of picric acid and sublimate gives good 
preparations. 
led to the introduction of a new stain, for which Platner suggests 
medullary sheath uncolored. Used at its full strength it stains 
other tissues, but with less intensity. 
An over-stain is easily reduced by dilute ammonia (five or six 
drops to a watch-glass full of water), or, preferably, by carbonate of 
— lithium, diluted ad libitum. A pure and intense nuclear stain may 
be thus obtained. Treated in this way, the accessory nuclei are 
stained in varying degrees of intensity, according to the stage of 
their development.! i 
It is a remarkable fact that these accessory nuclei, soon after their 
formation, become non-receptive to safranin or Victoria blue 4 R, 
while remaining stainable with nucleus-black. It would seem, as 
Platner remarks, that chromatin is composed of two substances, one 
of which is affected only by certain nuclear stains, while the other 
is receptive to a large number of stains, and especially so to nucleus- 
black and hematoxylin. 
Sections from preparations in Flemming’s fluid may be left 
twenty-four hours in a dilute solution of nucleus-black. The time 
of exposure to the decoloring fluid will vary according to the inten- 
sity of the stain received and the end to be reached. ‘The stain is 
permanent and well adapted to photographing. 
The Eggs of Ascaris megalocephala.—Platner recommends heat- 
ing to 50°C., for twenty to forty seconds, then hardening ia ascend- 
ing grades of alcohol. This method has the great advantage of 
killing instantly without injurious effects, and leaving the nuclear 
figures in a better state of preservation than can be reached by any 
other method hitherto used. The egg-sacks are placed in a test- 
tube plunged in a dish of hot water. This method will undoubt- 
edly be useful in other cases. 
1 Accessory nuclei arise from the chromatin of the nucleus, by a pro — 
cess of budding, and their development may be induced by starving tne 
nimal the sixth or seventh day, in the case of the salamander, 
