FREE BOOKS

Author's List




PREV.   NEXT  
|<   65   66   67   68   69   70   71   72   73   74   75   76   77   78   79   80   81   82   83   84   85   86   87   88   89  
90   91   92   93   94   95   96   97   98   99   >>  
cutting the lung or other organs where an interstitial support is needed. For a very thin object, a cork fitting any kind of a tube is to be split, and the object placed between the two parts; the cork is then thrust into the tube, and a sufficient degree of firmness will be obtained to allow cutting. The sections should always be manipulated with camel's hair brushes. Much practice will be required before dexterity is attained. _Methods of preserving the tissues_.--All water must be removed from the tissue, either by drying or by immersing it in rectified spirits, and then in absolute alcohol, and the alcohol driven off by floating it upon oil of clove or turpentine. The substances used to preserve the tissues are Canada balsam, Dammar balsam, glycerine, Farrant's solution, potassium acetate, spirits, naphtha, and creosote. The section is to be floated on to the slide or placed in position with a camel's hair brush. It should be spread out, and then examined under the microscope for the purpose of improving its position if necessary, or of removing any foreign particles. A drop of the preserving medium is then placed upon it, and another placed on the cover and allowed to spread out. The cover is then taken by a pair of pincers and inverted over the object, and one edge brought to touch the slide at one part of its margin. The cover is then gently lowered, and the whole space beneath the cover filled and the tissue completely saturated. If air bubbles show themselves, raise the cover at one corner and deposit a further quantity of the medium. The slide should be set aside for a few days. First, the excess of the medium must be removed; if it is glycerine, much of it can be removed by a piece of blotting paper, but the cover must not be touched, for it is easily displaced; that near the cover can be replaced by a camel's hair brush. A narrow ring of glycerine jelly should be placed around the edge of the cover, to fix it before the cement is applied. When this has set, a narrow strip of cement is to be put on, just slightly overlapping the edge of the cover and outside the margin of the jelly. Until it has been perfectly secured, a slide carrying glycerine must never be placed in an inclined position, as its cover will slide off. _Preservative media_.--Canada balsam may be prepared as follows: Place some pure Canada balsam in a saucer, and cover with paper to exclude dust; dry it in an oven at a temperature of
PREV.   NEXT  
|<   65   66   67   68   69   70   71   72   73   74   75   76   77   78   79   80   81   82   83   84   85   86   87   88   89  
90   91   92   93   94   95   96   97   98   99   >>  



Top keywords:

balsam

 

glycerine

 
position
 

removed

 

Canada

 

medium

 

object

 

tissues

 

alcohol

 
tissue

spirits

 

narrow

 
cement
 

margin

 

preserving

 
spread
 

cutting

 

support

 

excess

 

interstitial


displaced

 
easily
 

touched

 

blotting

 

completely

 
saturated
 

filled

 
beneath
 

bubbles

 
deposit

replaced
 

quantity

 

corner

 
needed
 

prepared

 

Preservative

 
carrying
 

inclined

 

temperature

 
exclude

saucer

 

secured

 
perfectly
 

applied

 

lowered

 

organs

 
overlapping
 
slightly
 

preserve

 
substances