6 Protoplasm : 



of an open network of fine threads upon which numerous granules 

 are rather irregularly placed, the spaces between the meshes being 

 filled with a still more watery substance. Nucleus. The nucleus, 

 on the other hand, while at rest, is occupied by what sometimes 

 appears as a much convoluted or ravelled thread, and at other 

 times as a very close network. On this thread or network numer- 

 ous granules are affixed, and as it does not stain deeply while the 

 granules are strongly dyed, the structure is easily made out. The 

 network is surrounded by a fine membrane which separates it from 

 the rest of the protoplasm, and the whole interior of the nucleus is 

 bathed in fluid. 



Structure in Animals. 



Animal cells and those of fungi and parasites differ from those 

 of ordinary vegetables in containing no plastids, and this is the 

 reason why they cannot feed on inorganic matter but have to 

 obtain their nutriment from substances originally elaborated by 

 chlorophyllous plants. On the other hand all, or at all events, 

 most animal cells contain a peculiar body called a centrosome, which 

 is not possessed by the cells of the higher plants, though found in a 

 few of the lower. The centrosome is a homogeneous body situated 

 near the nucleus, and is generally surrounded by a clear space 

 from which fine protoplasmic threads radiate on all sides. By 

 those who have made an exhaustive study of this body it is regard- 

 ed as a most important organ of the animal cell, and the centre of 

 forces which cause cell division. 



Huxley's Views. 



Professor Huxley, in his Article on Biology in The Encyclopedia 

 Britannica, wrote: "A mass of living protoplasm is simply a 

 "molecular machine of great complexity, the total results of the 

 "working of which, or its vital phenomena, depend on the one 

 "hand upon its construction, and on the other, upon the energy 

 "supplied to it ; and to speak of 'vitality' as anything but the 

 "name of a series of operations is as if one should talk of the 

 " 'horologity' of a watch." This dictum of the Professor has been 

 quoted and applauded again and again, but though he speaks of 

 the construction of the protoplasmic machine, he forgot for a 

 moment that no machine ever constructed itself, that they all re- 

 quired a designer and a constructor, and the ' horologity ' he speaks of 



