elementary part separated, showing the germinal matter and formed material-magnified 700 diameters. Fig. 37. The so-called mucous tissue of the umbilical cord showing the oval masses of germinal matter and the fibrous tissue or formed material, under a power of 130 diameters. Compare this figure with fig. 36. Fig. 38. A portion of the preparation represented in fig. 37 magnified 700 diameters. The relation of the germinal matter to the formed material seems to be the same as in other forms of fibrous tissue. The anastomosing nutrient tubes described by Virchow could not be demonstrated in this specimen. Fig. 39. A few of the muscular fibre-cells' from the wall of one of the arteries of the umbilical cord. PLATE VII. Illustrating the structure and growth of cartilage. Fig. 40. From the frog. a.-Very young cartilage composed of oval masses of germinal matter separated by a small quantity of soft and imperfectly formed intervening substance. b.-One of the masses of germinal matter which exhibits an outer portion which is only slightly coloured by carmine, and a central part more darkly coloured. The outer portion is gradually becoming converted into matrix. c. An elementary part showing zones of different ages. The outermost only is perfectly-formed cartilage; next come layers of germinal matter which are slowly undergoing conversion into cartilage, and lastly the nucleus is seen in the centre of the mass. d.An older elementary part consisting of fully-formed cartilage, recently-formed cartilage, germinal matter and the nucleus. e. Shows that not only does the germinal matter undergo conversion into cartilage at its external surface but that this alteration may occur as well in the central part. f, g.-Show |