Scottish National Antarctic Expedition : A Contribution to the Histology of 

 the Central Nervous System of the Weddell Seal (Leptonychotes weddellii). 

 By Harold Axel Haig, M.B., B.S. (Loud), -M.R.C.S. (Eng.), L.R.C.K (Lond.), 

 Lecturer in Histology and Embryology, University College, Curd ill'. Communi- 

 cated by Dr W. S. BKUCK. (With Two Plates and Nine Text Figs.) 



(MS. received June 18, 191:2. Head IWnnlM-i' -2. lull', [ssued separately Kel.rnary 17, 1913.) 



C O N T K N T S. 



PART I. 



(,<) The Spinal Cord. 

 (i) The Medulla < ll 

 (c) The Pons Varolii. 

 (rf) The Meseneephaloii. 

 (e) The Motor Cortical Aiva 



(j) The CVivl ,ell H in. 



(;/) The Oplic Thakuuuf. 



PART II. 

 The Pituitary Gland. 



PART I. 



INTRODUCTORY AND PRACTICAL DETAILS. 



The specimens submitted for examination were : 



(a) Portions of the brain (labelled Specimen XXXI.). 

 (6) Portions of spinal cord (labelled Specimen XXIV.). 



Both were in excellent condition as regards tixation and hank-nine- havinor been 



O o' O 



preserved for many years in a fluid composed of formol and 95 per cent, alcohol (the 

 fluid was also injected into the cerebral vessels). They were, previous to histological 

 examination, submitted to the following processes: 



i. Comparatively thin slices were taken from various regions and placed for 



twenty-four hours in absolute alcohol, 

 ii. Then transferred to acetone for twelve hours, 

 iii. Placed in xylol until permeated. 

 iv. Embedded in paraffin of melting-point 52 C. Sections were then taken 



with au improved form of the Cambridge rocking microtome, and lixed to 



slides by means of the albumen method. 



Staining of the *SV<Y/(///.v. 



The best stain for differentiating the grey and white matter was found to be 

 Weig&rfs method with acid fnchsin, used alone, or subsequent to treatment with 

 Delatield's hiumatoxylin. Other stains were tried (Bismarck brown with acid fnchsin 

 as counterstain, aniline blue-black, ha-matoxylin and orange-U., etc.), but acid-fuchsin 



(REPRINTED FROM THE TRANSACTIONS OK THE ROYAI, SoeiKTY ul KIUXl:ri!i:ll, Vol. \I.\III.. IT. M! Mil!) 



