346 TEGUMENTARY ORGANS. 



and moistened with aqueous or vitreous humour from the 

 animal, and left for a few minutes exposed to the air (it is 

 well to add to the aqueous or vitreous humour a few drops of 

 T y per cent, methyl blue .solution). After about ten to 

 thirty minutes the nerve-endings are seen to be stained, and 

 the sections are then brought into picrate of ammonia, and 

 treated as described in 119. 



653. Corpuscles of Krause (Cornea and Conjunctiva bulbi) 

 (DoGiEL, Arch.f. mik. Anat., xxxvii, 1891, p. 602; Zeit.f. wiss. 

 Mik., viii, 4, 1892, p. 519). A fresh bulb should be enucleated 

 in toto, and incised along aline running parallel to the equator 

 and 5 to 8 mm. behind the corneal margin. The anterior 

 segment thus obtained is freed from the ciliary body, lens, 

 &c., the conjunctiva being left in situ on the cornea. It is 

 then cut into pieces which are stained for an hour to an hour 

 and a half in rnethylen blue + aqueous humour, as described 

 in 117, and further treated for examination and preserva- 

 tion as described in 119. 



See also LONGWOKTH'S methods, Arch. f. mik. Anat., 1875, 

 p. 655. 



654. Papillae Foliatse of the Babbit (HEEMANN). See Zeit.f. 

 wiss. Mik., v, 4, 1888, p. 524. 



655. Olfactive Organs of Vertebrates (DOGIEL, Arch. /. mik. 

 Anat., 1887, p. 74). 



656. Organs of a " Sixth Sense" in Amphibia (MITROPHANOW) . 

 See Zeit.f. wiss. Mik., v, 4, 1888, p. 513. This paper con- 

 tains some details as to staining with " Wasserblau," for 

 which see also Biol. Centralb., vii, 1887, p. 175. 



657. Nerve-endings in Tongue of Frog (FAJEKSTAJN [FETTER- 

 STEIN], Arch, de Zool. exper. et gen., vii, 1889, p. 705; Zeit. 

 f. wiss. Mik., vii, 3, 1890, p. 357). Amongst other methods 

 for the study of the terminal discs, the methylen blue method 

 is recommended. Solution of 1 part methylen blue to 800 of 

 0'6 per cent, salt solution should be injected through the 

 abdominal vein (not through the vena cutanea magna), the 

 animal being curarised or etherised. After injecting, care 

 must be taken that air has access to the mouth. Injection 

 through the dorsal lymph- sac will also succeed, and simple 



