THE FROG. 21 



PLATE VI. 



THE FKOG. GENERAL HISTOLOGY (see Appendix G). 



FIG. I. Ciliated epithelium. 



Scraped from the roof of the mouth of a recently killed frog. 



Normal salt solution, afterwards stained with eosin. D. 3. 



FIG. II. Columnar epithelium. 



Scraped from the lining membrane of the small intestine. Treated as for Fig. I., D. 3. 



The four cells to the left retained their natural relationships, and in connection with 

 those numbered i and ii, the mucin secretion is indicated; ii is drawn in the act of 

 discharging the same. 



FIG. III. A portion of the Frog's mesentery, examined in water after two hours' 

 exposure to the sun's rays in silver nitrate solution D. 2. 



FIG. IV. i. A small piece of intermuscular connective tissue. 



Spirit material, stained with borax carmine. 



If no white fibres are readily visible, a piece of tendon should be teased up. 



ii. Pigment cells (of the mesentery) in various stages of development. D. 4. 



FIG. V. Hyaline cartilage. 



i. Thinnest part of the xiphisternum, after removal of its fibrous investment. Fresh, D.2. 



ii. One group of cells of the above, more highly magnified. F. 4. 



The nucleus of the uppermost cell has divided, prior to the division of the cell itself. 



FIG. VI. The fat-cell. 



i. Section of the corpus adiposum. Alcohol and borax carmine. F. 3. 



ii. Cells of the above, teased up fresh. Stained with eosiu. D. 3. 



iii. A ripe fat-cell. The fat-drops have united to form one large globule. 



For an account of the morphology of the corpus adiposum see Marshall (16) and 

 Bourne (3). 



FIG. VII. The blood, examined immediately after death. D. 4. 



i. Three phases in the life of the same corpuscle, at successive intervals of two minutes 

 each. 



ii. Phases in the union of two corpuscles. 



iii. A late stage in the fission of a white corpuscle. F. 3. 



At iv. are a number of red corpuscles seen on end. 



FIG. VIII. Transverse section of the spinal cord. 



On the right side the pia mater is shown, and more especially the large multipolar 

 nerve-cells of the anterior cornu. A. 3. 



Chromic Acid. Alcohol. Borax carmine. 



