drawing the 'cells' become smaller and the processes or tubes are seen to become narrower; then they appear solid and are lost in the matrix which is gradually becoming impregnated with calcareous particles.

Fig. 69. Muscular fibre-cells' from the circular coat of the aorta of a man who died from rupture of the arch. The tissue was torn if only very slight force was employed. These beautiful elementary parts with long radiating processes can hardly be called 'cells.' The processes are certainly fibrous. There is no possibility of distinguishing 'cell wall' and 'cell contents,' but the inner matter which is granular, gradually shades off into the fibrous substance of which the outer part of the processes is clearly composed.

The outer fibrous part of these elementary parts was not tinged by carmine; within this was a layer of tissue slightly reddened, and within this the colour was more intense, while the nucleus, which was situated furthest from the carmine solution, was very darkly coloured.