79 



The paraffin method is not advisable if the above method suf- 

 fices. If it is desired, however, after the dehydration, clear thor- 

 oughly with oil of cloves followed by xylene and infiltrate in paraffin 

 ( 52). In treating the sections, avoid alcohol as much as possible. 



-Section or in toto staining may be applied, preferably carmine 

 (not alkaline or acid formulae) . 



This important method has been elaborated largely through the 

 work of Bethe, Cajal, Dogiel, Huber, Retzius and others, for which 

 consult [6]. 



The method may be used for the staining of Neurofibrillae ; for 

 its applications for this purpose, consult the special articles. 



209. Neuroglia Stain. Tissue is fixed for 24 hours in copper 

 dichromate-sublimate-acetic (1/5%) mixture ( 16) and subsequently 

 mordanted 3 or 4 days in 2.5% copper dichromate. Imbed in paraffin, 

 Sections (5 to 10^) are fastened to the slide and the Benda stain is 

 used, as follows: (1) 4% ferric alum for 24 hours; rinse well in dis- 

 tilled water and (2) place for 24 hours in a dilute solution (amber 

 yellow) of sodium sulphalizarinate (concr. sol'n. in 70% alcohol 

 added to distilled water). Rinse in distilled water, blot with absorb- 

 ent paper, and stain (3) in a 1/10% aq. sol'n. of toluidine blue, 

 heating it until it steams, cooling and staining 15 minutes. (4) Rinse 

 with distilled water and treat for a few seconds with acid alcohol (70% 

 alcohol, 100 c. c.; concr. Hcl, 6 drops). (5) Blot with absorbent 

 paper and dehydrate rapidly with 95% and absolute alcohol. (6) 

 Differentiate carefully with creosote, to the right degree; (7) blot 

 with absorbent paper, and rinse in several changes of xylene. Mount 

 in balsam. Neuroglia fibers, a dark blue, neuroglia 'cells' a light 

 blue, axis cylinder and myelinic sheath red to brown, nuclei dark blue, 

 etc. 



This method may be used with fresh or formalin material, human 

 or animal. (Kingery). 



THE BLOOD. 



Special methods in the examination of the blood include (1) 

 Examining fresh; (2) Technic of staining blood films; (3) Deter- 

 mination of the number of red and white corpuscles per cubic milli- 

 meter; (4) differential counting of the white corpuscles; (5) De- 

 termination of the relative amount of hemoglobin; (6) Spectroscopic 

 examination of blood (hemoglobin), etc. (1) and (2) are briefly 

 given here; for (6) see [17]. 



