128 CHANGES IN BIOPLASM OF FOEMED CAKTILAGE. 



instead. Altered conditions may cause a given kind 

 of bioplasm, which, under favourable circumstances, 

 would form a high tissue of a special kind, with 

 peculiar properties, to produce a low, simple kind of 

 connective tissue; but under no circumstances do 

 altered external conditions determine the production 

 of a texture higher than that which the bioplasm was 

 destined to produce originally. The formative powers 

 of bioplasm will readily deteriorate or retrograde, but 

 will never advance under the influence of altered ex- 

 ternal circumstances. 



181. Changes occurring in the bioplasm of fully 

 fornied cartilage. — The formation of matrix or tissue 

 continues even in adult cartilage. Althouerh the 

 entire mass may undergo no alteration in size, new 

 tissue is produced to compensate for the shrinking 

 and condensation, which the tissue undergoes as it 

 advances in age. Slowly indeed are these changes 

 carried on, because the "matrix" is very slightly 

 permeable to fluids. But the bioplasm still has the 

 f0V)er to grow rapidly, and it will do so if the matrix 

 becomes more permeable, or if the access of the pabu- 

 lum to the bioplasm is facilitated by artificial means. 

 As in other cases the rapidity of the growth of bio- 

 plasm simply depends upon the supply of pabulum. 

 Let a thi^ead be passed through a healthy cartilage, 

 so as to make artificially a channel by which the 

 pabulum may reach the bioplasts more quickly, and 

 the operation will be very soon followed by their in- 

 crease in size, division, and multiplication. The 

 formed material in their immediate neighbourhood 

 will be softened and otherwise altered. 



Fatty matter is very often deposited by the bio- 

 plasm of cartilage. In some cases, the cavity in the 

 matrix of the cartilage seems to be entirely occupied 

 by the oil globule or globules. In the cartilage of 

 the ear of some of the smaller animals which are fat 

 and well fed, the so-called cartilage cells appear to be 



