730 
Notes. 
is essential to secure a very gradual stretching. This can be secured almost invari¬ 
ably by the above method if the water employed in flooding the basin is initially very 
cold. The danger of permanent adhesions of opposite sides of folds in the ribbon is 
thus avoided, and a perfect stretching secured for ribbons of the thickness of i //,. 
A sufficiency of albumin-water or other liquid fixative should in all cases be employed 
to avoid the stranding of the ribbon at any point on the slide before stretching is 
completed. 
In dealing with hard materials, an examination with a hand-lens sometimes 
shows that, even after stretching of the ribbon has continued for two or three minutes, 
that of the embedded materials is incomplete. In such cases a complete stretching is 
secured, with apparently no harmful effects by raising the temperature of the water 
in the containing vessel to the melting-point of the paraffin. 
The slide should be allowed to cool in every case before surplus fixative is 
removed, and the slide should be replaced on the rim of the basin and in contact 
with the water before the last portion of the fixative is removed. If this is attended 
to, full contact between ribbon and slide is secured. 
The main surplus of fixative should be drained away by allowing the slide to 
remain for a short period in an almost vertical position, or by means of blotting-paper 
which is not allowed to touch the sections. The last traces of unnecessary fixative 
are removed by three strips of blotting-paper, which are laid over the ribbon and 
lightly rubbed with the finger. 
A more efficient apparatus than the one above described can be made from 
a brass disc of 2 1 - in. diameter and J- in. thickness. The top of this is recessed in 
the lathe to a depth of about in., leaving a rim J in. in width. The hollow 
thus prepared corresponds to the concave base of the shrimp pot. Three lugs fitted 
with levelling-screws are fixed below the disc, and serve to raise the latter well above 
the bottom of the water-bath and to secure a levelling of the slide and an even distri¬ 
bution of the fixative fluid whereby any local stranding of the ribbon, during stretch¬ 
ing, may be avoided. Both the disc and the three lugs can be made of lead, instead 
of brass; it serves admirably and is easier to work in a laboratory lathe. The metal 
dishes used as water-containers can be obtained at any hardware shop at a cost of 
a few pence. W. HORTON. 
Hartley Botanical Laboratories, 
The University, Liverpool. 
