146 



Additional Note on Micro-Cements for Fluid Cells. 

 By Charles F. Rousselet, F.R.M.S. 



In the note I published in this Journal in November 1898 

 (Vol. YII., pp. 93-97), I advocated for closing fluid mounts the use 

 first of a coat of a mixture of damar and gold size, then four thin 

 coats of pure gold size, followed by a finishing coat of Ward's 

 brown cement at intervals of twenty-four hours. 



Further experience has shown that the addition of this last 

 coat is a mistake, as, by excluding the air, it prevents the 

 oxidation, and consequently the hardening, of the gold size. The 

 gold size therefore remains in a more or less semi-fluid state 

 under the brown cement, which is not good. I find that pure 

 shellac is not soluble in 2|-per-cent. formalin, and I therefore 

 now close fluid mounts as above, but with two coats of shellac 

 between the damar and gold size, omitting the brown cement 

 altogether, and hope this will prove satisfactory. 



Journ. Qttel-ett Microscopical Clv.h, Scr. 2, Vol. VIII., No. 49, November 1901. 



