FIXING AND PRESERVATIVE MEDIUMS 49 



attended with several inconveniences, one of the chief being that 

 its vapours are doubtless injurious to some persons at any rate, 

 causing irritation of the mucous tissues. It appears to be readily 

 decomposed by dust, in presence of which it becomes brown 

 or blackens rapidly, whilst it also renders fragile any organism 

 which may be left in any of its solutions for even a compara- 

 tively short time. Washing freely with water before placing 

 the subject in alcohol is the best method of obviating some of 

 its disadvantages. 



It has been added by Lo Bianco to sea-water containing 

 certain Radiolaria, in the proportion of a few drops at i per 

 cent, taking care, however, to wash the specimens well before 

 transferring them to the definite alcohol ; and with this acid 

 he has obtained the best results with Acineta fcetida. 



36. — Kleinenberg's Liquid (Lo Bianco, p. 441) 



Picric acid (saturated solution) . .100 parts 



Sulphuric acid (concentrated) . . . 2 „ 



Filter and add water (distilled) . . 300 „ 



This liquid, according to Lo Bianco, was one of the first 

 employed at the Naples Station for the preservation of marine 

 organisms, but, owing to its chemical composition, has been 

 found of little service excepting for histological research 

 and for the fixing of certain Protozoa (Gregarinidae), which 

 should remain therein for about an hour before their trans- 

 ference into weak alcohol. 



Chromic Acid. — Lo Bianco remarks (pp. 440, 441) that, 

 after alcohol, this acid is one of the most useful reagents, and 

 serves to kill and harden gelatinous and soft organisms, but 

 they must only rest for a limited time under its influence, other- 

 wise it gives an ugly colour and renders them fragile. All 

 subjects killed or hardened by it should be well washed in 

 spring-water. It is best employed as a mixture with osmic, 



4 



