444 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(4) Cutting and Mounting Sections. Directions are also given for obtain- 

 ing embryos from tbe earliest stages to the fourth day, and for their 

 examination as transparent or opaque objects. 



The rabbit is similarly dealt with, commencing with ova from one 

 to sixty hours old to embryos of fourteen days. 



Imbedding.* — Mr. J. S. Kingsley describes the following method 

 of imbedding : — 



" The substance to be imbedded is hardened after any of the usual 

 methods, and placed from alcohol into turpentine, then transferred to 

 a saturated solution of paraffin in turpentine, the same as in other 

 methods of paraffin imbedding. Here is where the novelty comes in. 

 The specimen is removed from the mixture, and the superfluous fluid 

 removed by means of blotting paper, and then placed on a cylinder of 

 paraffin (or paraffin and vaseline). A piece of stout iron wire is now 

 heated in the flame of a spirit-lamp, and with it a hole is melted in 

 the end of the cylinder, and the specimen then pushed into the melted 

 paraffin, and placed in any desired position. 



The advantages of the method are : the quickness with which it 

 may be performed, for from the time when the operation is begun 

 until sections can be cut is not over three minutes, while the melting 

 of so small an amount of paraffin prevents any injury to tissues by 

 overheating. In imbedding solid bodies a slight variation sometimes 

 results in the saving of more time. The specimen may be imbedded 

 directly from alcohol without the intervening turpentine, and then 

 when the section is cut it readily separates from the shaving of paraffin 

 without the use of turpentine to dissolve it. This, of course, applies 

 to solid bodies without cavities or irregular outline." 



Mounting Insects in Balsam without Pressure.! — Mr. H. Chad- 

 wick gives the following directions : — 



Preparation. — I. Soak the specimens in liquor potas?03 until they 

 are transparent. Wash well in distilled water, using a pipette and 

 camel-hair pencil. Transfer to 50 per cent, spirit, then to a small 

 quantity of pure spirit in a watch-glass or soaking bottle, and allow 

 them to stand for some hours. Then add oil of cloves, and allow the 

 spirit to evaporate. By this method, the formation of air-bubbles in 

 the interior of the specimens may generally be avoided. 



II. Wash well in distilled water. Soak in pure spirit or alcohol 

 for some days. Transfer to carbolic acid until sufficiently trans- 

 parent. Then transfer to oil of cloves, but many mounters do not 

 consider this necessary. This method should be used in all cases 

 where the integument is not too opaque to allow light to pass through 

 it before treatment, and it is especially useful in the study of the 

 muscles. 



Mounting. — Take a clean 3x1 slip, having a sunk cell in its 

 centre. Just inside the edge of the cell, equidistant from each other, 



* Amcr. Mon. Micr. Journ., iv. (1883) p. 58, from 'Scientific and Literary 

 Gossip.' 



t Micr. News, iii. (1883) pp. 105-6 (1 fig.). 



