left are seen some elongated cells with nuclei and nucleoli. These probably become spiral vessels.

Fig. 20. One of the large cells with thick walls, containing little starch, but exhibiting pores, which are, however closed externally by a thin layer of the original capsule (cell-wall).

Fig. 21. A piece of the wall of one of the cells figured in 20, magnified 700 diameters, showing the manner in which the material applied to the thickening of the wall, is added, layer after layer, upon the inner surface. The innermost layers are the uppermost represented in the drawing.

Fig. 22. Five young starch-holding cells of the potato, showing the outer thin layer of formed material (cell wall), the germinal matter (primordial utricle), with small starch globules precipitated amongst it; also the nucleus and nucleolus.

PLATE IV.

Cancerous growth situated in the Pharynx. The elementary parts represented in fig. 23 were present in the sputum. To illustrate the structure of a rapidly growing cancerous growth. Archives of Medicine. Vol. 11, p. 44.

Fig. 23. Shows the various forms of the cells or elementary parts. Many of the masses are clearly not cells, but fragments of a mass containing, irregularly scattered through it, nuclei or portions of germinal matter. At p is represented a piece from the lower part of which the nuclei and portions of the mass surrounding them have been broken off, leaving cup-shaped cavities in which they were lodged.

Fig. 24. Portion of the tumor itself removed after death.
Fig. 25. Portion of a cervical gland.

N

PLATE V.

To illustrate the structure of certain forms of white fibrous tissue.

Fig. 26. Connective-tissue, forming a network of rounded cords continuous with the areolar coat of a small artery. From the abdominal cavity of a frog. A part of the muscular coat of the artery is shown at a. A nerve is seen at b running in the external areolar coat. At c the bundle of nerve-fibres is seen to divide and several fibres are imbedded in the connective tissue of which the rounded cords are composed.

Fig. 27. d.-Small piece of one of the cords represented in the upper part of fig. 26 at b. Several nerve fibres are seen, and in the upper part of the drawing some very fine fibres. These last are probably altered nerve fibres. At e another portion of a true but very fine nerve fibre is represented. Three distinct fibres lie in a clear transparent matrix, the so-called tubular membrane. f.-A portion of one of the finest cords in fig. 26. Nuclei with branching fibres are seen, and the distribution of these is very similar to that of the fibres represented in the upper figure.

Fig. 28. The extremities of two elementary muscular fibres, showing their connection with the tendon, from the eye of the frog. The oval masses of germinal matter (considered by some to be nuclei and by others as spaces) are seen both in the muscle and tendon. Those in the muscle are connected with the formation of the contractile tissue while those in the tendon take part in its production.

Fig. 29. Periosteum from the frog showing the masses of germinal matter from which it is produced.

Fig. 30. White fibrous tissue Fascia from the frog.

Fig. 31. Tendo Achillis, kitten at birth, showing the "nuclear fibres" consisting of oval masses of germinal matter, with narrow intervening portions which have been described as consisting of yellow elastic tissue.