SOME METHODS FOB LOWER ANIMALS. 491 



form of the nucleus and nucleolus (BALBIANI et HKKNEGUY, 

 Cornpt. rend. Sue. de BioL, 1881, p. 131). 



Amongst useful reagents not mentioned in the following 

 descriptions of the methods employed by different authors, I 

 call attention to the Aveak solutions of alum, potash, and borax, 

 which serve to demonstrate the striations of the cuticle, and 

 the insertions of the cilia of Infusoria. 



See also MAGGI, Technica protistologica, Milano, 1895. 



879. Methods for quieting Infusoria. The narcotisation 

 methods, 18 to 22, are available for* this purpose. 



According to SCHURMA.YER (Jen. Zeit., xxiv, 1890, pp. 402 

 470; Zeit. f. u'iss. Hik., vii, 4, 1891, p. 493) nitrate of 

 strychnin in weak solution, 0*01 per cent, or less, gives good 

 results with some forms, amongst which are Stentor and 

 Carchesium. Antipyrin in concentrated solution (O'l per 

 cent.), or cocaine of 0*01 per cent., seems only to have given 

 good results as regards the extension of the stalk in stalked 

 forms. 



EISMOND (Zool. Anz., xiii, 1890, p. 723) has proposed a 

 mechanical means of slowing the movements of small 

 organisms (small worms and Crustacea as well as Ciliata). 

 He directs that a drop of thick aqueous solution of cherry- 

 tree gum be added to the water containing the organisms 

 (gum arabic and the like, it is stated, will not do). The 

 objects remain fixed in their places, with cilia actively moving, 

 and all vital processes retaining their full activity. 



CERTES (Bull. Soc. Zool. France, xvi, 1891, p. 93; Journ. 

 Boy. Mic. Soc., 1891, p. 828) has found that the method gives 

 excellent results. He has also found that an intra vitam 

 sta-in may be obtained by adding methyl blue or " violet 

 dahlia, No. 170," to the gum solution. 



A similar process has been worked out by JENSEN (after 

 STAHL ; see BioL GentralU., xii, 1892, 18, 19, p. 556 ; Zeit. f. 

 wit*. Mik., ix, 4, 1893, p. 483; Journ. Roy. Mic. Soc., 1892, 

 p. 891). A solution of 3 grammes of gelatin in 100 c.c. of 

 ordinary water is made by the aid of heat. This makes a 

 jelly at the normal temperature. It is slightly warmed, and 

 a drop of it is mixed in a watch glass with a drop of water 

 containing the organisms. This plan is said to afford great 

 facilities for the vivisection of Infusoria. 



