1887.] MICROSCOPICAL JOURNAL. 29 
drawn from the liquid, a considerable quantity of the latter must be taken in 
with it, and the deposit is, consequently, very much disturbed and diffused. 
To obviate this difficulty, a form of settling tube was devised some time ago, 
a description of which appeared in Dr. Deem’s Hand-book of Urinary Analy- 
sis, published in New York. It consisted ofa straight glass tube, large enough 
to admit a urinometer, and open at each end, the top being provided with a 
lip for pouring, and the bottom made conical, the lower end being of a con- 
venient size for slipping over it a short piece of rubber tubing, provided with 
_a pinchcock and auxiliary pointed tube. 
This piece of apparatus was a decided advance upon the conical test-glass, 
but it still had a disadvantage in the presence of an organic substance (india rub- 
ber), which might prejudice the results, to say nothing of the agitation and 
mixing of the different parts of sediment in passing the different corners, the 
ends of the two glass tubes, and the constriction in the rubber tube caused by 
the pinchcock. 
The tube before us has, we think, none of these objections, while it is quite 
as convenient in other respects. It consists of a glass tube, open at top and 
bottom, the lower part being tapered to quite a small opening and the upper 
part provided with a tubulated cap, which fits the settling tube proper rather 
closely. The joint between the two is secured and made water-tight by means 
of an elastic band cut from a piece of thin rubber tubing, in size a little smaller 
than the glass tube. The latter may be of any convenient width, say ? of an 
inch to 1 inch, and 6 to 8 inches long. At the upper end of the small tube 
joined to the cap a short piece of rubber tubing, provided with a pinchcock, 
may be used, as any sediment which may be caused by contact with the 
rubber at this part of the apparatus will lodge in the lower bend of the tube 
immediately below and not be carried into the large tube. Of course, the 
neatest way would be to have a glass stopcock blown upon the upper end of 
the bent tube, but this would increase the cost, and would be really unneces- 
sary unless a liquid were to be examined, which, like permanganate of potas- 
sium, would be decomposed by the rubber. 
To fill the tubes, the parts are put together in such a manner as to be water- 
tight; the lower finely-pointed end is inserted into the urine or other liquid, and 
-suction is applied at the other end, either by means of a rubber bulb or in any 
other convenient way. It is necessary that the tube be extzrely fad/of the liquid, 
for any air bubbles which might be allowed to remain therein would, by their 
contraction or expansion, disturb the sediment to the extent, possibly (if the 
temperature of the room should be raised a few degrees), of forcing the latter 
out of the tube. After the deposit has accumulated at the bottom, it can be 
easily dropped upon a slide by manipulating the stopcock at the top. In this 
way a number of samples of the sediment can be obtained in the order in which 
they have fallen to the bottom of the tube. 
If it be desired to make use of a settling tube, about which there shall be no 
rubber at all, the whole tube (bottom and top) can be made of one piece, with 
a glass stopcock at the top, as suggested above. These tubes can be obtained 
of Wm. Betz, glass-blower, 98 Fulton street, New York. The mounting of 
the instrument may be accomplished in a variety of simple ways, and can be 
left to the ingenuity of the manipulator. 
On treating chicks for section-cutting. 
We have printed in another portion of this number of the ,Jowrzad a letter 
from Mr. Jay L. Smith upon hardening and cutting sections of chick embryos. 
We have cut a great many series of chick sections of all stages, from the un- 
incubated blastoderm to five days’ chicks, and have hardened by a great 
