312 Miscellaneous. 



of hairs, feathers, fish-scales, whalebone, &c., are best preserved. It 

 may be also used with advantage for mounting specimens of many 

 minute animalcules provided with a hard integument, such as 

 cheese-mites, the itch-insect, small freshwater Crustacea, and the 

 like. It is likewise the best preservative for vegetable preparations, 

 whose cell-walls or vessels have undergone a partial incrustation, and 

 is also very useful for displaying the shells or loricce of the siliceous 

 Bacillariee and Diatomaceoe. 



In using it, one only requires to lay the object on a slide, and to 

 moisten it with a drop of the solution, taking care, at the same time, 

 to remove the air-bubbles which may be formed here and there. Two 

 pieces of paper, corresponding to the thickness of the object, are next 

 pasted to the extremities of the slide, and the whole is then covered 

 ■with a second glass plate of the same size. If it should now be found 

 that too little fluid has been applied to the object, or that part of it 

 has run oif, a drop of the solution may be applied to the edge of the 

 slide, and will find its way between the glasses by capillary attraction. 

 A piece of thin paper may be inserted between the glasses, to promote 

 the flow of the fluid towards the preparation, or to rectify the position 

 of the object when it has become displaced. 



For attaching the strips of paper to the glass slides in this and 

 other cases, the best material that can be used is starch paste, with 

 which a little arsenious acid is mixed, in order to prevent the forma- 

 tion of a species of mould which is otherwise apt to gather round the 

 preparations. — Vol. ii. p. 347-350. 



Of late I have discovered a fault in this mode of mounting prepa- 

 rations. In many which have been preserved in drops of the chloride 

 of calcium solution, there have formed numerous branches of a species 

 of Hygrocrocis, which spread from preparation to preparation, and 

 from box to box, threatening totally to destroy all specimens which 

 have been put up in this way. I have consequently discontinued the 

 practice of mounting specimens in chloride of calcium solution, to 

 which the air still has access ; and when I now employ this or any 

 other fluid, am careful to exclude the influence of the atmosphere by 

 touching the edges of the covering-plate with a cement which I have 

 elsewhere described (see p. 314). This procedure has the additional 

 advantage of not requiring the use of a saturated solution : it may be 

 diluted, in proportion to the delicacy of the specimen, with from two 

 to ten parts of water. — Vol. iii. p. 470. 



II. Canada Balsam. 



The method of mounting objects in Canada Balsam is too well 

 known to require description. 



III. Creosote Solution. 



This fluid may be prepared either by distillation with water, or by 

 filtering a saturated solution of creosote in one part of alcohol of 

 s. g. 867, after mixing it with twenty parts of water. It is useful 

 for all preparations of muscle, cellular tissue, tendon, ligament, car- 



