58 THE CELL 



I have for some time held the opinion, which, for reasons that 

 I will state later (vide Chap. VI.), I still hold to be worthy of con- 

 sideration, that the central corpuscles are generally constituent 

 parts of the resting nucleus, since after division has taken place 

 they enter its interior, and whilst it is preparing for division come 

 out again into the protoplasm. Only in rare cases do the central 

 corpuscle or corpuscles remain in the protoplasm itself, whilst the 

 nucleus is resting, and then to a certain extent they represent a 

 subordinate nucleus in addition to the principal one. This theory 

 would explain the fact that, even with the more recent methods and 

 most improved optical instruments, the central corpuscles as a rule 

 cannot be demonstrated near the resting nucleus in the protoplasm of 

 the cell. 



V. Upon the Molecular Structure of Organised Bodies. 

 In order to explain the chemico-physical properties of organised 

 bodies, Nageli (V. 17, 18 ; II. 27, 28) has advanced a micellar 

 theory, which, although undoubtedly to a great extent hypothetical, 

 is very useful in rendering many complicated conditions more 

 easy of comprehension, and above all more easily pictured to the 

 imagination. A short abstract of this micellar theory, which de- 

 serves attention, if only on account of the strictly logical manner 

 in which it has been worked out, will not be out of place 

 here. 



One of the most remarkable properties of an organised body is 

 its capacity of swelling up, that is to say, of absorbing into its 

 interior a large, though not unlimited, quantity of water, with the 

 substances dissolved in it. This may take place to such an extent 

 that in an organised body only a small percentage of solid sub- 

 stances may be present. 



The body increases in size in proportion to the amount of 

 water absorbed, shrinking up again when the water is expelled. 

 Hence the liquid is not stored up in a pre-existent cavity, 

 which before was filled with air, as in a porous body, but 

 becomes evenly distributed amongst the organised particles, 

 which, as the body swells up, must become farther and farther 

 pushed apart, being separated from one another by larger and 

 larger envelopes of water. In spite of the absorption of so much 

 water, none of the organised substance becomes dissolved. In this 

 respect the phenomenon differs from that which takes place with a 

 crystal of salt or sugar, which on the one hand does not possess 

 the power of swelling up, and on the other becomes dissolved 



