1885.] Microscopy. 919 
which it is supported on the copper tube. A bit of cotton in the 
bottom of the test tube protects the mercury bulb of the regu- 
lator or thermometer from any jars against the hard test tube. 
The holes in the sides of the test tube allow the water of the bath 
to come in direct contact with the mercury bulbs and at the same 
time they are up high enough to keep the mercury from running 
into the bath should either of the mercury bulbs break while in 
the tube. The copper bath is supported ina square box-table, 
the top of the bath being flush with that of the table. 
This table essentially is a box on four legs, with a hole in the 
top slightly more than twenty-eight inches in diameter, and with 
a door at one end. The bath is supported on four props that rest 
on the lower shelf of the table, and around the inside of the table 
is a lining of common tin to protect against possible accident. 
By this means a steady flame is obtained and the loss of heat is 
reduced toa minimum. And by grouping the regulator, ther- 
moméetor and gas pipe near the center of the bath, hindrances are 
practically done away with. There is also connected with the 
gas jet a small home-made glass Bunsen burner that is attached 
to the glass gas tube a little above the bath. It is very con- 
venient for warming dip tubes, lifters, etc. In so large a bath as 
this two flames are required, but both are burned very low. The 
one burner is connected directly with the gas jet and the other by 
way of the regulator. After the bath has, so to speak, been once 
set it runs on uniformly and requires no attention. Itis regulated 
by putting a thermometer through the hole in one of the lids into 
the dry chamber and shutting off the regulator burner when the 
chamber is warm enough. The temperature, as indicated by the 
thermometer that dips into the water, is always a few degrees 
higher than that of the dry chambers. When the thermometer 
inthe water indicates a temperature of 60° C. the basins are 
warm enough to keep the hardest grade of paraffine melted. The 
whole stands at a convenient working height, about three feet 
eight inches, and is very satisfactory—HHenry F. Nachtrieb, Fellow 
Fohns Hopkins University, 
SUGGESTIONS AS TO THE PREPARATION AND USE oF SERIES OF 
SECTIONS IN ZootomicaL INstTRuCTION.—It is convenient to have 
in the laboratory prepared series of certain types, so that the 
student may supplement the information he has acquired from 
