The Lumbosacral-coccygeal Cord of the Macaque Monkey. 89 



' Technique. — The monkey was injected by Mann's* method, with picro- 

 corrosive formaldehyde solution : — f 



Formula. 



Boiling water 100 c.c. 



Sublimate 2 - 5 grammes. 



When dissolved, add — 



Picric acid ... 1 gramme. 



Allow to cool, and immediately before use add — 



Formol 10 c.c. 



The spinal cord was allowed to remain in the vertebral canal until the 

 following day, when it was removed with the spinal ganglia, and placed in 

 50 per cent, alcohol. The cord was then cut at different levels, and the 

 various portions of it were dehydrated through gradual transference to alcohols 

 of increasing strength, cleared in xylol, and embedded in paraffin (melting 

 point, 52°). The cord was found to be well fixed throughout its length. 



The lumbo-sacral-coccygeal cord was cut in serial sections, 10 fi and 20 fi 

 thick, with the large Cambridge rocking microtome, which cuts flat sections, 

 and the sections mounted on albuminised slides.J A certain number of 

 serial sections were also cut at each of the levels of the dorsal (thoracic) and 

 cervical cord, and similarly mounted. 



After the removal of the paraffin by xylol, the sections were treated with 

 absolute alcohol and then with iodine potassium iodide solution to remove the 

 excess of corrosive sublimate and to decompose the albuminates of mercury. 

 The iodine solution was removed with methylated spirit and distilled water. 

 The sections were stained with eosin and toluidin blue§ (eosin, 10 minutes ; 

 toluidin blue, 2\ minutes ; or for a longer time in similar proportions), and 

 mounted in xylol balsam. 



Three drawings were made at the level of each pair of spinal nerves, the 

 sections being selected from the upper, middle, and lower portion of the line 

 of entrance of the dorsal nerve root. The drawings were made with an 

 Abbe - Camera Lucida (Zeiss), a Zeiss microscope with the tube at 158, 

 a No. 4 compensating ocular, and a Wray 3-inch lens. The magnification was 

 equal to 20 diameters, except in dealing with certain sections in the lower 

 regions of the cord, when it became advisable to use a magnification equal to 

 40 diameters. For this purpose a Leitz No. 1 lens was employed. The drawing 

 paper was placed on a Bernhard drawing board (Zeiss), the board being level. 



* Mann, G., 1 Zeit. f. Wiss. Mikr.,' vol. 11, p. 482 (1894). 



t Mann, G., ' Methods and Theory of Physiological Histology,' 1902, p. 97. 



% Mann, G., 'Zeit. f. Wiss. Mikr.,' vol. 11, 1895, pp. 479—494. 



§ Mann, G., ibid. 



H 2 



