THE PRESERVATION OF MICROSCOPIC SPECIMENS. 



283 



hydrochloric acid. The strength of the calcium solution must be 

 regulated according to the nature of the tissues ; woody cells bear 

 complete saturation, whilst a weaker solution is preferable for 

 young tissues. 



(5.) Sugar-water, for preparations wliicli become too muck altered 

 by glycerine or chloride of calcium. The sugar element checks the 

 otherwise invariable decomposition and the accompanying disturb- 

 ance of the liquid. In order, also, to prevent any fungous growth, 

 the solution may be mixed with a little corrosive sublimate. This, 

 of course, always requires hermetic sealing. 



In addition to these preservative liquids, numerous others have 

 been proposed chiefly adapted for animal preparations. A few of 

 those most used may be mentioned here. 



The mixture recommended by Pacini a modification of the so- 

 called Goadby's fluid consists of 



Corrosive sublimate, 1 part, 

 Pure chloride of sodium, 2 parts, 

 Glycerine (25 Beaume), 13 parts, 

 Distilled water, 113 parts. 



This mixture should be allowed to stand two months, and then 

 be diluted with three times its weight of distilled water and 

 filtered through blotting paper. For the preservation of blood- 

 corpuscles, nerves, ganglia, cancer-cells, as well as delicate protein- 

 ous tissues, this is said to be excellent. 



Similar mixtures are also employed in different proportions in 

 the Pathological Institute of Berlin ; according to Cornil 1 they 

 are composed as follows : 



No. 1 is intended for vascular tissues of warm-blooded animals ; 

 No. 2, for those of cold-blooded ; No. 3, for pus-corpuscles and 

 1 Quoted by H. Frey : " Das Mikroskop," 5th ed. p. 127. 



