1887.] MICROSCOPICAL JOURNAL. 167 
bination of lenses can be adapted to meet the requirements of different 
objectives, and to the various forms of lanterns. At least one firm of Ameri- 
can opticians has lately introduced a form of condenser that is said to work 
well, but it does not commend itself to our mind. There is still opportunity 
for the application of the principles that have already been suggested, and 
the construction of a more efficient condenser than has yet been offered for 
sale. 
We are indebted to Professor S. H. Gage for a copy of his really valuable 
‘ Notes on Microscopical Methods,’ which he has kindly sent to us in this 
far-away land. No doubt it has already received due notice in the ourzat, 
so it is only left for us to acknowledge its arrival and return thanks for it. 
Along with it comes also a request from the author to examine the epithelium 
of the mouth of the large salamander that inhabits some of the lakes of Japan. 
This is the second letter we have received concerning the Cryptobranchus or 
Megalobranchus, which is said to attain a length of three feet; and so much 
interest seems to attach to it that we shall endeaver to capture one on the first 
opportunity, after which it will be time enough to consider the epithelium. 
APRIL 22, 1887. 
Klementary histological studies of the Cray-fish.—V. 
By HENRY L. OSBORN. 
CHAPTER II.—THE ‘ LIVER.’—( Continued from page 152.) 
1. Preparation of the slide.—For the study of the gross anatomy and 
histology of the, ‘ liver’ of the cray-fish one, if sufficiently expert, may use 
the same creature as has already served in the study of the green gland, but 
we should advise a beginner to take a fresh live creature for the purpose. 
This should be killed as before directed. (See pp. 81 and 82). To expose 
to view the organ called the liver the shell from the dorsal part of the body 
must be very carefully removed. To effect this raise the shell over the ceph- 
alo thorax at its hinder extremity ; that is, where it meets the abdomen, and 
with a pair of fine scissors cut beneath it. Direct the scissors forward and 
toward the side and remove the shell from the entire back well forward to- 
ward the head. After the dorsal part of the carapace has been carefully re- 
-moved, the same operation must be repeated upon the dorsal part of the 
anterior abdominal rings to remove the shell covering the two or three most 
forward of them. When the shell has been thus carefully removed, a num- 
ber of organs will be exposed:—In the middle line in front a thin semi- 
transparent sack (1), the stomach; behind it, if the operation has been 
sufficiently careful, the heart still pulsating ; on either side of (2) the heart, 
extending under it (3) the ovary or testis, according to the sex of the animal ; 
on either side beyond the reproductive organ, and below it reaching forward 
to the stomach and backward to the first or second abdominal segment (4), 
the liver. 
These organs may be carefully separated with dull teasing needles, not 
torn asunder or broken through, but gently pressed apart and submerged in 
strong alcohol for several hours preparatory to the study of the gross anatomy 
of the organ. The specimen for histological examination must be treated 
differently. : 
To prepare the material for sections the ‘ liver’ of one side should be re- 
moved without any tearing or pulling of the organ. This can be accom- 
plished if the other organs are sacrificed to some extent, if the sharp scissors 
are skilfully used and the tissue is manipulated with a section lifter and gentle 
b) 
