544 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
point. It is then cut off at the right length and the cut end softened by 
heat and then quickly pressed upon some hard surface, so as to form a 
sort of head. The tacks are then arranged in rows in some shallow dish, 
previously oiled, and enough plaster of Paris poured around them to 
form a layer from 1J to 2 cm. deep. When this hardens, the tacks are 
firmly held in an upright position, and all that remains to be done is to 
place the plaster disc in the bottom of the glass jar. 
To use the apparatus, fill it partly full of alcohol (60-80 per cent.). 
As the specimens are imbedded on the corks, transfer them to this jar, 
sticking each cork upon a tack.” 
An improved Method of preparing large Sections of Tissues for 
Microscopic Examination.* — Mr. J. C. Webster writes : — “ Hitherto we 
have employed two methods of preparing large sections for microscopic 
study, viz. the freezing and the celloidin. In the former the Hamil- 
ton or Bruce microtome is used, and in the latter the Schanze. 
Each of these processes has connected with it certain difficulties which 
limit the range of its employment. 
The objections to the first method are the following : — 
(a) It is impossible to prepare delicate or friable tissues in large 
thin sections, because, after being cut, they either break into pieces when 
placed in water, or during the mounting process get torn and destroyed. 
The placenta, for example, cannot be cut into sections suitable for the 
finest microscopical work, as the villi and the blood-corpuscles in the 
maternal sinuses are almost entirely scattered when placed in fluid. 
( b ) The relations of parts cannot be preserved. Thus, for example, 
one cannot mount undisturbed a section through bladder and uterus, or 
through brain and membranes. 
(c) The difficulties and discomforts connected with the working of a 
large freezing microtome are considerable. 
The objections to the second method are : — 
(a) It is impossible to prepare sections thin enough for examination 
by high powers. Those which can be made are only fit for study with 
low powers, or for lantern demonstration. This is the case with even 
the most easily cut tissues. 
(b) The microtome employed — the Schanze — is complicated and 
expensive; its knife is with great difficulty kept sharp, and does not 
always cut large sections in slices of uniform thickness. 
(e) The materials used in preparing the tissues for cutting are 
expensive. 
The method which I am about to describe is not only free from these 
important objections, but possesses several distinct advantages. 
(1) Preparation of Tissues . — Tissues may be hardened by any of the 
known methods, the last stage, however, being a twelve or eighteen 
hours’ soaking in absolute aloohol. 
The following method gives splendid results : — 
Place the fresh tissue in a boiled saturated solution of corrosive sub- 
limate for one night. Then wash in water, and place for 24 hours in 
a mixture of one part of methylated spirit and two of water ; then in 
a mixture of equal parts for two days. Gradually increase the propor- 
* llep. Lab. R. Coll. Physicians Edinb., iii. (1891) pp, 266-70. 
