216 CHAPTEE XVII. 



RoDGET {Arch, de Physiol., 1873, p. 603) employed solutions 

 as weak as 1 : 750, or even 1 : 1000, exposing tlie tissues to 

 their action several times over, and washing them with water 

 after each bath. 



The Heetwiqs take, for marine animals, a 1 per cent, 

 solution (Jew. Zeit. Naturlc, xvi, pp. 313 and 324). 



The HoGQANS [Joiirn. of Anat. and Physiol., xv, 1881, 

 p. 477) take for lymphatics a 1 per cent, solution. 



TouENEux 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 {Arcli. mile. Anat., 1876, p. 619) 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 

 ammonia-nitrate solution has the advantage of impregnating 

 absolutely nothing but endothelium or epithelium ; connective 

 tissue is not affected by it. 



Ranviee's injection-mass for impregnating endothelium is 

 given under " Injection." 



Dekhuysen {Anat. Anz., iv, 1889, No. 25, p. 789) has 

 applied to terrestrial animals the method of Haemee for 

 marine animals (§ 356). For details nee previous editions. 



Regadd {Joiirn. Anat. et Pliyx., xxx, 1894, p. 719) recom- 

 mends for the study of lymphatics a process devised by 

 Renaut, for the details of which see also previous editions. 



353. Other Salts of Silver.— Alfbeow [Arch. Pliys., i, 1874, p. 694) 

 employs the picrate, lactate, acetate, and citrate, in solution of 1 . 800, 

 and adds a small quantity of the acid of the salt taken (10 to 15 drops of a 

 concentrated solution of the acid to 800 c.o. of the solution of the salt). 

 This decomposes the precipitates f orm.ed by the action of the silver salt on 

 the chlorides, carbonates, and other substances existing in the tissues. 



Regaud and DtrBEBUiL (O.-R. Ass. Anat., 5 Sess. 1903, p. 122) take a 

 fresh solution of protargol or a mixture of equal parts of 1 per cent, 

 protargol and 1 per cent, osmic acid, thus avoiding precipitates. 



354. Silver Nitrate : Reduction. — Reduction may be effected 

 in other media than distilled water. 



V. Recklinghausen washed his preparations in salt solution 

 before exposing them to the light in distilled water {Arch. 



