MOUNTING INFUSORIA. 



305 



Infusoria/ such as the Monosiga Steinii and Salpingceca con- 

 vallaria, shown in Fig. 250. He states that they may be 

 sealed up after treatment with osmic acid without the addi- 



FIG. 250. 



tion of any other preservative, and that it will be found the 

 smaller and most delicate flagelliferous species are equally 

 amenable to this treatment, preserving their flagella, and 

 even, in the case of the Choano-Flagellata, their sarcode 

 collars in a life-like form. Many fluids have been described 

 for these purposes, some will be given in the recipes at 

 the end of the book, but the beginner should remember 

 never to use a fluid in a cell unless he is thoroughly 

 acquainted with the action the fluid has, or has not, upon its 

 walls or on the cements or varnishes used in connection 

 with it. If these points were more studied, fluid mounts 

 would not be looked upon with so much ill-favour as they 

 are now. 



Objects mounted in glycerine should always be put in a 

 cell, and if the cover be put on in the manner described for 

 mounting in carbolised water, and diatoms, dry, the slip can 

 be easily cleaned from any superfluous glycerine. After 

 this, put the slide on the turntable, and describe a neat ring 

 of brown varnish, finally finishing with a broad ring of 

 white zinc varnish, as before described. 



x 



