CHAPTER XXXI. 



NERVOUS SYSTEM — GENERAL METHODS. 



736. Introduction. — Microscopical research into the struc- 

 ture of the nervous system pursues two ends. Either it is 

 desired to elucidate the internal organisation of nerve-cells 

 and nerve-fibreSj the processes employed to this end forming a 

 group of cytological methods, or it is desired to study the 

 forms of nerve-cells, the distribution of the divers groups 

 of nerve-cells in the grey matter, the connections that are 

 formed by means of nerve-fibres between them, and to follow 

 out the course of the tracts of fibres that enter into the 

 constitution of the white matter of the cerebro-spinal axis, 

 the processes employed forming a group of the anatomical 

 methods of neurology. 



A large proportion of the methods used in the study of 

 nerve-tissue in peripheral organs having already been des- 

 cribed in the chapters on " Methylen Blue," " Impregnation 

 Methods," " Tegumentary Organs," and "Muscle and 

 Tendon," the following chapters are chiefly devoted to 

 methods for the study of the central nervous sj'stem. 



For minute details concerning tlie dissection and hardening of the 

 encephala of Man and the larger Voi'tebrates see Meecier, Les Coupes 

 (hi Si/sthne Nerreux Central, 1894, Pai-is, Rueff) ; Dejeeinb, Atuitomie 

 das Centres Nerveiix. Paris, 1895; Bevan Lewis, Tlie Bvmrm Brain, 

 London, Clnircliill ; Obeksteinee, Aiileitung hiein Studium dcs Banes 

 il. ncrvosen Centvalnrgane hn (jesvndcn ii. hravlicn Zustande. Leipzig, 

 Toeplitz ; VAN Walsbm, Verh. Alcad. Witevsclc. Amsterdam, -vii, J899; 

 BoNViciNi, Zcit. wiss. Mile, xxvi, 1909, p. 410 ; Baton. Die liut. Unfer- 

 siuhuiigensmetlwden des Nerven systems, Wiirzburg, 1905; and Si'iBL- 

 MEYBR, Techvih d. mikro. TJntersuclmmq d. Ncrveiisystems, Berlin, 1911, 

 and Venderovics, Avat. Anz., xxxix, 1911, p. 414. 



Fixation. 



737. Fixation by Injection. — Fixation, in the proper sense 

 of the word, is, of course, out of the question in the case of 



