22 ATLAS OF BIOLOGY. 



FIG. IX. Transverse section across the scia.tic nerve. Alcohol and hseinatoxylin. A. 3. 

 The sheath, p.n., is often laden with fat. 



FIG. X. A small portion of one of the nerve-bundles of Fig. IX. highly magnified. F. 3. 



FIG. XI. A series of preparations to show the structure of the nerve-fibre, and the 

 leading types of nerve-cells. 



i. A small portion of a nerve-fibre, teased up, and exposed to the action of 1 p.c- 

 osmic acid for two hours. The segment between the two nodes of Eanvier figured, is seen 

 to bear one nerve-corpuscle. D. 2. 



ii. An isolated fibre from a nerve-trunk, examined immediately after death. The lower 

 portion of the preparation is drawn after treatment with 1 p.c. osmic acid. F. 4. 



iii. A small portion of a dead nerve-fibre similar to the above. F. 4. 



iv. A unipolar nerve-cell from the ganglion of a spinal nerve. Teased fresh in eosiu. D. 3. 



These cells vary very much in size ; that drawn was a small one. 



v. A bipolar nerve-cell from a sympathetic ganglion. Teased fresh in eosin. F. 2. 



vi. A multipolar nerve-cell from the anterior cornu of the spinal cord (* of Fig. VIII.). 



This preparation shows the continuation of the nerve-cell into an axis-fibre, and was 

 obtained by teasing up a portion of an anterior nerve-root, isolated together with a small 

 piece of the grey matter of the cord. Fresh, stained eosin. D. 3. 



vii. One of the smaller fusiform nerve-cells from the grey matter of the spinal cord. 

 Teased fresh. Eosin. D.4. 



In Figs. IV. and V. the sheath is indicated by a faint line. 



FIG. XII. Transverse section of the retina. Picric acid. Alcohol. Borax carmine. 

 F. 3. 



The parts shaded darkly are those which stain deepest. 



The cells, n.o., usually but two rows deep, may sometimes be three deep as here figured. 



FIG. XIII. Transverse section across the middle of the belly of a small muscle of the 

 hind limb. 



For purposes of comparison with the nerve, the section drawn was of the same absolute 

 size as that of the nerve-trunk, Fig. IX. Alcohol and borax carmine. A. 3. 



The ingrowths of the perimysiuin marked * are very delicate, but they may be readily 

 traced as they are generally pigment-laden. 



FIG. XIV. One fibre of the above muscle-section, more highly magnified. 

 Drawn to the same scale as the nerve-fibres in Fig. X. 



FIG. XV. Two preparations of striped muscular fibre. 



i. A fresh fibre one portion of which has been ruptured, rendering clear the so-called 

 sarcolemma. D. 3. 



