1890.] MICKOSCOPICAL JOURNAL. 9 



A Point in the Use of Oil of Cloves. 



By W. hatchet JACKSON, 



DEPUTY LINACRE PROFESSOR OF ANATOMY, OXFORD, ENG. 



Oil of cloves is very generally employed to clear up sections that have 

 been dehydrated previously to mounting in Canada balsam or Dammar 

 varnish. It sometimes happens that the sections turn milky on the 

 addition of the oil. I found that the students in the morphological 

 laboratory here regarded such sections as useless and spoilt, a belief, as 

 I have reason to suppose, not confined to them. 



The remedy is a simple one. If a small quantity of oil is poured on 

 the sections whether already fixed to the slide or not, and then the 

 whole is gently warmed for a short time, an operation readily performed 

 on the water-bath used to melt the paraffin for imbedding purposes, the 

 milkiness disappears. If it does not disappear at once, the oil on the 

 slide should be poured off, fresh oil added, and the heating repeated. 



The rationale of the process depends upon the fact that the milkiness 

 is due to a combination between the essential oil and a small residual 

 quantity of water. I have seen this compound termed a camphor in 

 a chemical text-book ; but whatever its nature may be, it is readily 

 soluble by the aid of w^armth in an excess of the essential oil. 



If heating the slide is objectionable, repeated soaking in absolute 

 alcohol will effect the same end. But it is much more troublesome and 

 takes a longer time. — Zoologischer Anzeiger^ Dec. 2, 1889, p. 630. 



Report upon the Postal Club Boxes. — IX. 



By queen MAB. 



The first box of the season arrived December 4, after a five-months' 

 intermission. The delay is explained by the fact that there has been 

 negligence in a few localities about properly forwarding the boxes. It 

 is of greatest importance that each member adhere strictly to the rules 

 of the Club, and thus make possible the circulation of a large number 

 of slides. From thirteen to eighteen boxes of six slides each w^ere sent 

 out last year. It is hoped to circulate as many within the next seven 

 months. 



Box B. — This is of interest, both for what it is and for what it sug- 

 gests. The German laboratories have helped to give an impetus to 

 American microscopy within the last few years, and the preparation of 

 certain classes of objects has reached a degree of perfection little short 

 of marvellous. But the permanent preparation of objects, which is of 

 comparatively recent origin, has made no such advances. Indeed, one 

 often sees an incongruity between skilful preparation and unskilful 

 preservation. Labor is almost wasted which might easily be made ef- 

 fective. There is, however, a diversity of opinion, even among our 

 most noted preparers, as to the best methods of permanent preparation. 

 Some insist that balsam is the best medium for certain classes of ob- 



