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189 .] Microscopy. 1145 
to vertebrate embryology in general, by the careful study of a few 
human embryos. Only a glance at the new edition of Quain’s 
“Anatomy” will convince any one of this fact. 
Of a dozen human embryos, less than: six months old, which have 
come into my possession during the last few years, only one has been 
found well preserved and suited for careful study. For this reason I 
address this note especially to those who in the fature will be kind 
enough to send me material, 
In cases of early abortion the physician that attends pays no atten- 
tion whatever to the embryo, or only preserves it carelessly in alcohol. 
Often it is impossible to find the embryo within the blood and particles 
which are extruded. If in all these cases the suspected material were, 
without previous examination, placed simply in seventy per cent. 
alcohol, most valuable specimens would often be obtained. When the 
ovum comes away unruptured, it nearly always ruins the specimen to 
examine it. It should be placed at once ina large quantity of Miiller’s 
fluid, or in alcohol. If these are not at hand the ovum should be kept 
temporarily in a large open-mouthed bottle until the hardening fluid 
can be obtained. The specimen, even if not opened, can be injured 
very easily by handling or by wrapping it with cotton or cloth. In 
all these cases it is not advisable to throw injured specimens away, for 
poor material is of value for dissection, and certainly is better than 
none at all. 
Gynecologists, who are more especially interested in this subject, 
frequently have beautiful collections of specimens, and are by no 
means inclined to part with them. Yet the advancement. of embry- 
ology has shown that it is necessary to destroy, or rather to lay into 
sections, the embryos before they can be studied properly. After a , 
good specimen is once sectioned, the whole embryo or any part of it 
can be modeled quite easily on a large scale. This is necessary before 
the parts can be studied properly, and it requires a great deal of time 
and a considerable amount of costly apparatus, For this reason the | 
embryologist feels justified in asking the gynecologist to part with his 
highly prized material. 
Those physicians who have small laboratories, and are acquainted 
with the ordinary technique of hardening, should by all means harden 
specimens in Perenyi’s chromonitric acid, in Kleinenberg’s alcoholic 
picrosulphuric acid, in ten per cent. nitric acid, orin saturated solution 
of corrosive sublimate. Others who are not familiar with the above 
technique should use Miiller’s fluid or seventy per cent. alcohol. 

The latter i is in general the best, and an Amount of the alcohol equal 


