514 METHODS FOE INVERTEBRATES. 



jelly. For rapid examination after killing in alcohol, transfer to 

 absolute alcohol for thirty minutes, and clear in " white " creosote. 

 (LEIPER, in Science of the Sea, London. John Murray. 1912.) 



For fixing, most recent authors recommend sublimate solutions ; 

 chromic solutions seem to have a tendency to make the worms 

 brittle. 



But, according to ZUR STRASSEN (Zeit. wiss. ZooL, liv, p. 655), 

 Bradynema rigidum ought to be fixed for at least twelve hours in 

 mixture of Flemming. 



AUGSTEIN (Arch. Naturg., Ix, 1894, p. 255) takes for Strongylus 

 filaria Mayer's picro-nitric acid. 



VEJDOVSKY (Zeit. wiss. ZooL, Ivii, 1894, p. 645) advises for 

 Gordius 0-5 per cent, chromic acid (twenty-four hours). 



Lo BIANCO employs for marine forms concentrated sublimate or 

 picro-sulphuric acid. 



Looss (ZooL Anz., xxiv, 1901, p. 309) prefers hot (80 to 90 C.) 

 alcohol of 70 per cent. 



GLAUE (Zeit. wiss. ZooL, xcv, 1910, p. 554) kills Ascaris in a hot 

 mixture of 100 parts of saturated sublimate, 100 of alcohol, and 1 of 

 acetic acid. 



Staining is frequently difficult, and sometimes alcoholic carmine 

 234A, is the only thing that will give fair results. 



BRAUN (see Journ. Roy. Mic. Soc., 1885, p. 897) recommends that 

 small unstained Nematodes be mounted in a mixture of 20 parts gelatin, 

 100 parts glycerin, 120 parts water, and 2 parts carbolic acid, which is 

 melted at the moment of using. Canada balsam, curiously enough, is 

 said to sometimes make Nematodes opaque. 



Demonstration of living Trichinae. BARNES (Amer. Mon. mik. Journ., 

 xiv, 1893, p. 104) digests trichinised muscle (of the size of a pea) in a 

 mixture of 3 gr. of pepsin, 2 dr. of water, and 2 minims of hydrochloric 

 acid, kept at body temperature for about three hours. The flesh and 

 cysts being dissolved, the fluid is poured into a conical glass, and 

 allowed to settle ; the trichinae are drawn off from the bottom with a 

 pipette, got on to a slide with water and examined on a hot stage. 



GRAHAM (Arch. mik. AnaL, 1, 1897, p. 2.16) isolates Trichinae by 

 macerating for one or two days in 2 per cent, acetic acid, staining with 

 aceto -carmine, and teasing. 



966. Nemertina. My best results have always been obtained by 

 fixing with cold saturated sublimate solution, acidified with acetic 

 acid. The other usual fixing agents, such as the osmic and chromic 

 mixtures, seem to act as irritants, and provoke such violent muscular 

 contractions that the whole of the tissues are crushed out of shape by 

 them. 



