606 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Rapid Method of Making Permanent Specimens.* — Dr. T. S. 
Cullen describes a rapid method of making permanent specimens from 
frozen sections by the use of formalin. Knowing that specimens 
hardened in this fluid show almost perfect preservation of the cellular 
structure, it occurred to him that it might be used in the preparation of 
frozen sections. An excellent permanent specimen may be made in the 
following way : — The tissue to be examined having been frozen is cut, 
and the sections placed in 5 per cent, watery-solution of formalin for 
3-5 minutes, in 50 per cent, alcohol for 3 minutes, and in absolute for 
1 minute. The tissue is now thoroughly hardened and can be treated 
as an ordinary section, and stained and mounted in the usual way. The 
blood is lost in frozen sections as a rule, but if the specimens be first 
fixed in formalin and then frozen, the blood is preserved, although it 
does not stain very distinctly. Dr. Cullen says that given a piece of 
tumour from the operating-room it is possible to give as definite a report 
in 15 minutes as one would be able to give when examining the alcoholic 
or Muller’s fluid specimen at the expiration of two weeks. 
New Use of Formic-aldehyde, j — MM. Koehler and Lumiere describe 
a new use of formic-aldehyde as a preservative agent for the bodies of 
mammals. They find that, if doses varying from 50 to 150 ccm. of a 
one-fifth solution are injected into the digestive tube by the mouth and 
anus, and into the carotid of a guinea-pig, the animal may be hung up 
in a dry place and left in the open air for some weeks. In this condition 
the animal does not become in the least deformed. A specimen which 
had been thus treated four months earlier was, when exhibited, found to 
have the tissues absolutely free from putrefaction. The hairs were 
perfectly intact and the animal had kept its form and was found in a 
state of preservation which could not be obtained by any other process. 
Formalin as a Fixative instead of Osmic Acid.:}: — Herr A. Durig 
finds that formalin is more effective than osmic acid in Ramon y Cajal’s 
method; it penetrates deeper, is more certain, and cheaper. 
For fixing he used a gradation of 0*5 to 15 per cent, solution of 
formalin, with variable strengths of potassium bichromate, and there- 
after the silver nitrate process. 
Formalin as a FixativeJ — Prof. P. Lachi refers to a note by Dr. A. 
Durig on this subject, and points to the previously published results of 
experiments made with this method by Prof. Hoyer, Dell’ Isola, and 
himself. 
Hew Method of Preserving Large Specimens. || — Drs. H. Brand 
and L. Driiner describe the method they employ in the investigation of 
the nervous system of fish in order to obtain a uniform condition of pre- 
servation throughout large specimens. The method consists in intro- 
ducing the fixing solution through the vascular system. 
The fish is chloroformed, the heart exposed and a short glass tube 
attached to the bulbus aortae. The glass tube is connected by india- 
rubber tubing with the flask containing the preserving liquid. A second 
* Bull. Johns Hopkins Hospital, vi. (1895) p. 67. 
t Bibliograph. Anat., i. (1895) pp. 31 and 2. 
X Anat. Anzeig., x. (1895) pp. 659-60. § Tom. cit., pp. 790-1. 
|| Jena. Zeitschr. f. Naturw., xxix. (1895) pp. 435-42. 
