472 NEUmSOMES 



then rinses them with distilled water and stains them in 5 per cent, 

 solution of methylen blue, B pat. 



LuxENBURG (Neurol. Centrbl., xviii, 1899, p. 633) stains paraffin 

 serial sections either with Nissl's soap methylen blue or with thionin, 

 as Lenhossek. 



PoLUMORDWiNOW (Ztschr. wiss. Mikr., xvi, 1899, p. 371) fixes in 

 Gilson's mixture and uses for staining 1 part of a 1 per cent, solution 

 of toluidin blue to 119 of distilled water alkalised with 1 of sodium 

 carbonate. 



Picromarine has been successfully used by Messner {Journ. Psychol. 

 Neurol., xviii, 1912, p. 204 ; xx, 1913, p. 256). Sections of alcohol 

 material, imbedded in celloidin or not, are washed in water and then 

 stained for five minutes in a warm diluted solution of Ranvier's picro- 

 carmine. After a quick wash, they are differentiated in 3 per cent, 

 hydrochloric acid, dehydrated, and mounted as usual. In the case of 

 the spinal cord, medulla oblongata, and pons, the method also succeeds 

 if material was fixed in formalin. 



EiNARSON {Am. Jotirn. Path., viii, 1932, p. 295), after experimenting 

 with many dyes, recommends gallocyanin as the best stain for Nissl 

 granules. A variety of fixatives may be used ; 96 per cent, alcohol 

 (five to six days), alcohol-formalin (twenty-four to forty-eight hours), 

 sublimate-formol (twenty-four hours), formol-alcohol-sublimate (eight 

 to twelve hours), Zenker with acetic acid (about twenty hours) and 

 neutral formalin (20 per cent, for three to four days) all give good 

 results. Sections are cut in paraffin and are stained in gallocyanin 

 0-3 grm., chromalum 10 grm., distilled water 200 c.c. 



1004. Other Modifications and Methods for the Basophil Substance of 

 Nerve-cells. See Farrar, Rev. Netirol. and Psychiat., iii, 1905, p. 578 ; 

 Ilberg, Neurol. Centrbl., xv, 1896, p. 831 ; Goldscheider u. Flatau, 

 Norm. u. jmth. Anat. d. Nervens, Berlin, 1898, or Ztschr. wiss. Mikr., 

 xvi, 1899, p. 102, and Nissl's remarks thereon, Deutsche Ztschr. Nerven- 

 heilk, xiii, 1899, p. 348 ; Cox, Anat. Hefte, x, 1898, p. 98 ; Int. Monat- 

 schr. Anat., xv, 1898, p. 216 ; Auerbach, Monatschr. Psychiat. u. 

 Neurol., iv, 1898, p. 31 ; Myers, Anat. Rec, ii, 1908, p. 434 ; Savini, 

 E. u. Th., Centrbl. Bakt., 1. Abth., xlviii, 1909, p. 697 ; Mosse, Arch, 

 mikr. Anat., lix, 1902, p. 403 ; Mentz v. Krogh, Centrbl. Bakt., I Abth., 

 Orig., Iviii, 1911, p. 95 ; Johnston, Anat. Rec, xi, 1916, p. 297. 



1005. Neurosomes. This term was first used by Held to 

 indicate certain granules which since 1895 he succeeded in staining 

 in nerve-cells by means of the method described hereafter. Two 

 years later he included under the same heading minute, sharply- 

 delineated rods of fairly uniform size which stained by the acid 

 fuchsin method of Altmann and the iron-haematoxylin methods of 

 Heidenhain and Benda. These rod-shaped bodies were after- 

 wards identified by Cowdry {Int. Monatschr. Anat., xxix, 1913, 

 p. 473) as mitochondria, but the term " neurosomes " was retained 

 to indicate the granules which can be shown by Held's erythrosin- 

 methylen-blue method or one or other of its modifications. 

 As pointed out by Cowdry, they are irregular in size and shape and 

 more numerous in the cone of origin of the axon. They are 

 seldom, if ever, seen after fixation in fluid containing osmic acid, 

 which is most suitable for mitochondria, while they are best 

 stained after fixing in Carnoy's fluid, picro-sulphuric acid and 



