THE society's NOTE-BOOKS. 119 



Dermanyssus. — These appear to be very nearly alike from all 

 kinds of birds, except that from the tom-tit, which is a most extra- 

 ordinary creature, having the second pair of legs turned back, and 

 reaching a long way beyond the whole length of the mite. 



J. Beaulah. 



Dermanyssus, to avoid the curling up of the legs in mounting. 

 — When the animal can be got alive I have avoided this " curling " 

 by allowing it to walk on the slide ; then drop tolerably cool 

 glycerine jelly on to it, and whilst it is trying to grasp the situa- 

 tion, with all its li7?ibs exteiided^ drop the warm cover on, and on 

 examining when cool the object will be found to be well displayed, 

 colour natural, and no air bubbles. 



J. C. Thompson. 



Bird Parasites, to mount. — My usual plan is to catch them 

 alive, if possible (with a needle dipped in turpentine), and 

 immediately put them into a bottle of turps. When they have 

 been soaking a few hours for the small ones, and longer for the 

 larger ones, lift them out with a tube, and deposit a drop of turps 

 on the slide with two or three parasites in it. Arrange with a 

 needle, and then, taking a small quantity of balsam on a needle, 

 touch the slide near the objects, draw a thread of balsam across 

 and round about them, then put aside for the turps to evaporate. 

 Afterwards a drop more balsam and a cover will settle that slide. 

 By adopting this method I have seldom had any trouble with the 

 smaller kind of parasites. 



H. R. BouLT. 



Santonine. — I subjoin my process for preparing this slide. 

 Having dissolved from three to six grains of santonine in a drachm 

 of chloroform, I place a sHde on the turn-table, and take a small 

 drop of the solution in a pipette, and, giving the wheel a rapid 

 motion, cover a sufficient space, and with a point make a ring 

 round it. I then remove, and subject it to such a degree of heat 

 as experience dictates, until crystallisation is completed. The 

 slide is now ready for mounting dry. Balsam is destriiciive. In 

 order to view it effectively, I place the analysing prism m a hioiim 

 position, and then turn the polariser until it gives the selenite 

 a salmon colour, which produces the most brilliant results. A very 

 small move of the analyser reduces the effect. 



A. Nicholson. 



