442 SOME ZOOLOGICAL METHODS. 



hydrated, and mounted in balsam. No differentiation of the 

 stain is necessary. 



See also the somewhat similar methods of VIALLANES (Ann. 

 d. Sci. Nat., xiii, 1892, p. 354; Journ. Roy. Mic. 8oc., 1893, 

 p. 260). 



826. Nerve and Muscle of Arctiscoida (DOYEKE, Arch. f. mik. 

 Anat., 1865, p. 105). A score or so of Milnesium tardigradum 

 are collected (it is well to have a large number, as the process 

 by no means succeeds with all individuals) and put into a 

 test-tube with water that has been deprived of its air by 

 boiling. A drop of oil is run on to the surface of the water, 

 so as thoroughly to exclude the air. After twenty-four to- 

 forty-eight hours the animals will be found, not dead, but 

 fixed and extended in a cataleptic state; the circulation of the 

 perivisceral fluid has ceased, the pigment of the cuticle has 

 disappeared or collected into patches that are no hindrance to 

 observation, the entire animal has gained in transparency,, 

 and the nervous and muscular systems stand boldly out. The 

 animals are examined in boiled water, unless it be wished to 

 study the phenomena of resuscitation, in which case spring 

 water should be used. 



827. Sarcolemma of Insecta (THANHOFFEE, ibid., 1882, p. 27), 

 In order to demonstrate the two plates of the sarcolemma, 

 digest muscle (of an insect) either in the stomach of a living 

 animal (by wrapping it in gauze and introducing it through 

 a fistula) or in artificial gastric juice (in the former case 

 several hours, in the latter half to one hour, at the tempera- 

 ture of the room in summer). Examine in gastric juice. 



828. Phalangida (ROSSLEE, Zeit. f. wiss. Zool., xxxvi, 1882, 

 p. 672). The animals are killed in boiling water; the water 

 is allowed to boil up several times, so that the albumen of the 

 tissues may be coagulated; they are then brought into alcohol, 

 first of 70, then 90 per cent., then absolute, until all water is 

 removed from them. They are then imbedded in soap. The 

 soap is remelted and allowed to cool once or twice, in order 

 to get the objects thoroughly penetrated. Sections are then 

 made, and stained on the slide with some colouring matter 

 dissolved in absolute alcohol. 



Paraffin was tried for imbedding, but gave no good results, 



