200 METALLIC STAINS {(IMPREGNATION METHODS). 



order to avoid the formation on their surfaces of deposits of chlorides 

 and albuminates of silver. 



These impregnations only succeed with fresh tissues. 



352. Silver Nitrate : the Solutions to be employed (RANVIER) .- 

 The solutions generally employed by RANVIER vary in strength from 

 1 : 300 to 1 : 500. Thus 1 : 300 is used for the epiploon, pulmonary 

 endothelium, cartilage, tendon ; whilst a strength of 1 : 500 is 

 employed for the phrenic centre, and the epithelium of the intestine. 

 For the endothelium of blood-vessels (by injection) solutions of 

 1 : 500 to 1 : 800 are taken. 



M. DUVAL (Precis, p. 229) takes solutions of 1, 2, or at most 

 3 per cent. 



v. RECKLINGHAUSEN used, for the cornea, a strength of from 

 1 : 400 to 1 : 500 (Die Lymphgefasse, etc., Berlin, 1862, p. 5). 



ROBINSKI (Arch, de Physiol., 1869, p. 451) used solutions varying 

 between 0-1 and 0-2 per cent., which he allowed to act for thirty 

 seconds. 



ROUGET (Arch, de PhysioL, 1873, p. 603) employed solutions as 

 weak as 1 : 750, or even 1 : 1000, exposing the tissues to their action 

 several times over, and washing them with water after each bath. 



The HERTWIGS take, for marine animals, a 1 per cent, solution 

 (Jen. Zeit. Nattirk., xvi, pp. 313 and 324). 



The HOGGANS (Journ. of Anat. and PhysioL, xv, 1881, p. 477) 

 take for lymphatics a 1 per cent, solution. 



TOURNEUX and HERRMANN (ROBIN'S Journal de I 'Anat. , 1876, 

 p. 200) took for the epithelia of Invertebrates 3 : 1000, and in some 

 cases weaker solutions, for one hour, washing out with alcohol of 

 90 per cent. 



HOYER (Arch. mik. Anat., 1876, p. 649) takes a solution of nitrate 

 of silver, and adds ammonia to it until the precipitate that is formed 

 just redissolves, then dilutes the solution until it contains from 

 0-75 to 0-50 per cent, of the salt. This ammonio-nitrate solution has 

 the advantage of impregnating absolutely nothing but endothelium 

 or epithelium ; connective tissue is not affected by it. 



RANVIER' s injection-mass for impregnating endothelium is given 

 under <: Injection." 



DEKHUYZEN (Anat. Anz., iv, 1889, No. 25, p. 789) has applied to 

 terrestrial animals the method of HARMER for marine animals 

 ( 356). For details see previous editions. 



REGAUD (Journ. Anat. et Phys., xxx, 1894, p. 719) recommends 

 for the study of lymphatics a process devised by RENAUT, for the 

 details of which see also previous editions. 



