THE NERVOUS SYSTEM. 571 



This completes the differentiation . A very weak solution of sulphurous acid answers as well 

 as or better than the sulphite-oxalic mixture. If differentiation is not sufficient, rinse in 

 water and repeat the process. After differentiation, dehydrate, clear, and mount as usual. 



It is often advantageous, especially in younger fcetuses, to fix in copper bichromate, 3 

 per cent, to 5 per cent., 9 vols. + formalin i vol., and then harden a week or more in copper 

 bichromate, 3 per cent. These specimens should not be over i /2 an inch in thickness. 



For all Weigert methods, the most satisfactory fixation may be had by injecting the 

 bichromate-formalin mixture into the blood vessels. Specimens fixed and preserved in 

 formalin may be used for staining by the Weigert method. Mordant pieces in copper 

 bichromate 3 per cent, about a week or use the methods given in Mallory and Wright's 

 "Pathological Technic." 



For further details and other modifications of Weigert's methods, the student is referred 

 to the books on technic mentioned in the Appendix. 



References for Further Study. 



BARDEEN, C. R.: The Growth and Histogenesis of the Cerebrospinal Nerves in Mam- 

 mals. Am. Jour, of Anat., Vol. II, No. 2, 1903. 



DEJERINE, J.: Anatomic des centres nerveux. Tome I, Ch. 2 and 3. 



EDINGER, L. : Vorlesungen iiber den Bau der nervosen Zentralorgane. Seventh Ed. 



EDINGER, L. The Relations of Comparative Anatomy to Comparative Psychology. 

 Jour. ofComp. N enrol, and Psychol., Vol. XVIII, No. 5, Nov., 1908. 



FLECHSIG, P. : Einige Bemerkungen iiber die Untersuchungsmethoden der Grosshirnrinde 

 insbesondere desMenschen. Berichten der math.-phys. Klasse d. Kb'nigl.- Sachs. Gesellsch. d. 

 Wissensch. zu Leipzig. 1904. See also Johns Hopkins Hosp. Bull., Vol. XVI, 1905, pp. 



45-49- 



HARDESTY, I.: On the Development and Nature of the Neuroglia. Am. Jour, of Anat., 

 Vol. Ill, No. 3, July, 1904. 



HARRISON, R. G. : Further Experiments on the Development of Peripheral Nerves. 

 Am. Jour, of Anat., Vol. V, No. 2, May, 1906. 



HARRISON, R. G.: Observations on the Living Developing Nerve Fiber. Anat. Record, 

 Vol. I, No. 5, 1907. 



HARRISON, R. G.: Embryonic Transplantation and Development of the Nervous 

 System. Anat. Record, Vol. II, No. 9, 1908. 



HERRICK, C. J.: The Morphological Subdivision of the Brain. Jour, of Comp. N enrol, 

 and Psychol., Vol. XVIII, No. 4, 1908. 



His, W. : Zur Geschichte des menschlichen Riickenmarkes und der Nervenwurzeln. 

 Abhandl. der math.-phys. Klasse der Konig. -Sachs. Gesellsch. d. Wissensch., Bd. XIII, 1887. 



His, W. : Zur Geschichte des Gehirns, sowie der centralen und peripherischen Nerven- 

 bahnen beim menschlichen Embryo. Abhandl. d. math.-phys. Klasse d. Konig.-Sdchs. 

 Gesellsch. d. Wissensch., Bd. XIV, 1888. 



His, W.: Die Neuroblasten und deren Entstehung im embryonalen Mark. Abhandl. d. 

 math.-phys. Klasse d. Konig. -Sachs, d. Wissensch., Bd. XV, 1890. Also Arch. f. Anat. u. 

 Physiol., Anat. Abth., 1889. 



His, W.: Ueber die Entwickelung des Riechlappens und des Riechganglions und iiber 

 diejenige des verlangerten Markes. Verhandl. d. Anat. Gesellsch. zu Berlin, 1889. Also 

 Abhandl. d. math.-phys. Klasse d. Kdnig.-Sdchs. Gesellsch. d. Wissensch., Bd. XV, 1889. 



His, W.: Die Entwickelung des menschlichen Rautenhirns vom Ende desersten bis zum 



