CHAPTER XIX. 



217 



Air .... 1-000 

 Methyl alcohol . . 1 -323 

 Distilled water . . 1 -336 

 Sea water . . . 1-343 

 Solution of white of egg . 1 -350 

 Absolute alcohol . . 1 -367 

 Acetate of potash, satu- 

 rated aqueous sol. . 1-370 

 Glycerine with an equal 



quantity of water . . 1-397 

 Chloride of calcium, 90 per 



cent, in water . . -411 



Glycerine, Price's . . -460 



Oil of bergamot - . . -464 



Paraffinum liquidum . -471 



Olive oil ... -473 



Oil of turpentine . . 1-473 



Glycerine, " concentrated " 1 -473 



Gilson's Baume au Camsal 1 -478 



Gilson's Euparal . . 1-483 



Terpinol . . . 1-484 



Castor oil 1 -490 



Xylol . . . 1-497 

 Cedar-wood oil, not thick- 

 ened .... 1-510 

 Crown glass . . . 1-518 

 Cedar- wood oil, thickened . 1 -520 

 Gum damar . . . 1-520 

 Xylol balsam . . . 1-524 

 Oil of lemons . . . 1-527 

 Oil of cloves . . *. 1-533 

 Canada balsam (solid) . 1-535 

 Creasote . . . 1-538 

 Colophonium . . . 1-545 

 Carbolic acid . 1 -549 

 Oil of anise seed . . 1 -557 

 Oil of cinnamon (or cassia) 1-567 

 Anilin oil . . .1 -580 

 Sulphide of carbon . . 1-630 

 Tolu balsam . . . 1-640 

 Monobromide of naphtha- 



lin .... 1-660 

 Solution of sulphur in sul- 

 phide of carbon . . 1 -750 



It will be seen that cedar oil has nearly the index of crown glass 

 (this is true of the oil in the thick state to which it is brought by 

 exposure to the air not of the new, thin oil, which is less highly 

 refractive) ; it therefore clears to about the same extent as Canada 

 balsam. Clove oil has a much higher index, and therefore clears 

 more than balsam ; cinnamon oil higher still. Turpentine and 

 bergamot oil have much lower indices, and therefore clear less. 



Watery Media. 



401. Isotonic and "Indifferent" Liquids. The old distinction 

 of " Indifferent " liquids, and those which have some action on 

 tissues, appears to be misleading more than helpful ; ' for no medium 

 is without action on tissues except the plasma with which they are 

 surrounded during the life of the organism ; and this plasma itself 

 is only " indifferent " whilst all is in situ ; as soon as a portion of 

 tissue is dissected out and transferred to a slide in a portion of plasma 

 the conditions become artificial. 



Water may be employed for the examination of structures that 

 have been well fixed ; but this is by no means applicable to the 

 examination of fresh tissues. It is very far from being an " in- 

 different " liquid ; many tissue elements are greatly changed by it 

 (nerve-end structures, for instance), and some are totally destroyed 

 by its action if prolonged (for instance, red-blood corpuscles). 



