HOYER'S SHELLAC MASS. 237 



water from a tap furnished with an india-rubber tube. Leave 

 for some weeks in water, rinse, and put up in glycerin, or a 

 mixture of glycerin, alcohol, and water in equal volumes. 



487. Hochstetter's Modification of Schiefferdecker's Mass 

 (Anat. Anz., 1886, p. 51 ; Journ. Roy. Hie. Soc., 1888, p. 159). 

 Kaolin is rubbed up with ether, to which cobalt blue, chrome 

 yellow, or cinnabar is added. To this, celloidin solution of 

 the consistence of honey is added. 



Other Masses. 



488. Budge's Asphaltum Mass (Arch. f. mik. Anat., xiv, 1877, 

 p. 70) . A large quantity of asphaltum has benzol poured on 

 it, and is allowed to stand for several days, and then preserved 

 for use. Before injecting add J to ^ benzol, and filter. Chlo- 

 roform and turpentine may also be used as solvents. Used 

 for injecting the juice-canals of cartilage by the method de- 

 scribed 1. c., or by puncture. 



489. Hover's Shellac Mass (Arch.f. mik. Anat., 1876, p. 645). 

 Place a quantity of good shellac in a wide-necked flask and 

 add just enough alcohol (of about 80 per cent, strength) to 

 cover the shellac. Leave it for twenty-four hours, and then 

 warm it in a water-bath to complete the solution. When 

 cool, dilute, if necessary, with alcohol to the consistency of a 

 thin syrup and strain through moderately thick muslin. The 

 solution thus obtained may be coloured by the addition of 

 anilin colours in (filtered) concentrated alcoholic solution, or 

 of granular pigments suspended in alcohol. Of these, cinnabar 

 gives the finest colouration, and may be employed for corro- 

 sion preparations (anilin colours may also be used for this 

 purpose, but then they are not permanent). Berlin-blue and 

 yellow sulphide of arsenic are useful. A mixture of the two 

 gives green. Freshly-precipitated sulphide of cadmium gives 

 a fine permanent yellow. The pigments should be rubbed up 

 to fine powder with water, and alcohol added ; let the mix- 

 ture settle, pour off the dilute alcohol and add strong alcohol. 

 Shake in a flask, by which means the coarser particles are 

 brought to the bottom of the liquid, and at this moment pour 

 off the supernatant fluid which contains the finer particles 

 only. Add this to the shellac solution and strain through 



