SUMMARY OF CURRENT RESEARCHES RELATING TO 
39 
• )dl 
preserving cultivations of bacteria for museum purposes. Formalin, 
which, has a tanning action, is best employed in conjunction with subli- 
mate. The process of conservation is best begun with a solution of 
moderate strength, and gradually increased to pure formalin, as the 
colours, if any, are thereby better retained, and the crumpling, which is 
more or less inevitable, much diminished. This reagent acts well with 
all media except potato, and the water used for diluting it should be 
previously boiled. Some of the author’s preparations were fixed in the 
following manner. They were placed in an exsiccator containing form- 
alin instead of sulphuric acid, in order to tan the surface of the medium. 
They were then covered with a 1 to 10 solution of formalin containing 
0*1 per cent, of sublimate. This was afterwards changed for a some- 
what stronger solution, and the test-tubes eventually hermetically 
sealed up. 
Preservation of Marine Animals in Formaldehyde.* — Dr. Th. 
Pintner has obtained excellent results by using 1 per cent, solution of 
formaldehyde in the preservation of Medusas, Sponges, and the like. 
The form and colour are very jserfectly retained, and the organisms are 
usable for histological or anatomical purposes. 
(3) Cutting-, including- Imbedding and Microtomes. 
Orienting Small Objects for Sectioning.^ — Mr. W. Patten’s method 
for orienting large numbers of small objects is as follows : — Small 
strips of glazed writing-paper, marked with two sets of raised j^arallel 
lines running at right angles to each other, are cut, and at suitable 
intervals a very small drop of thick collodion and clove oil, about the 
consistence of honey, is added. The drops are arranged close together 
along one of the ribs that run lengthwise of the pap>er. The object to 
be imbedded is cleared in clove or bergamot oil, not turpentine. It is 
then raised on the point of a knife, and after the excess oil is drawn off, 
transferred to a drop of the thick collodion. It may then be adjusted 
at leisure and will stay in any desired position. 
When half a dozen or more objects are oriented in reference to the 
cross lines (which are to be parallel to the section planes), the whole 
thing is to be placed in turpentine. This washes out the clove oil and 
fixes the objects very firmly to the paper. When submerged in tur- 
pentine, the relation of each object to the orienting lines can be deter- 
mined under the Microscope with greater precision than before. 
The paper with the attached objects is now placed in the paraffin 
bath and finally removed and covered with paraffin in the usual way. 
After cooling in water the block is trimmed and the softened paper 
peeled off, leaving the objects in the paraffin close to the under surface 
of the block. This surface is now marked by the orienting lines of the 
rubbed paper, and also by the record numbers which before imbedding 
were written with a soft pencil on the paper. The block is now fixed 
on the microtome, and the objects cut one after the other, as though 
a single object had been imbedded ; or a number of them may be cut 
together, if they have been arranged with that object in view. For 
* Yerh. Zool.-Bot. Ges. Wien, xliv. (1894) p. 8. 
t Amer. Natural., xxviii. (1894) pp. 360-1. 
