CHAP, iv.] OF THE GENERAL CONDITIONS OF GROWTH. 295 



truth. So true is it, that we may sometimes abridge or lengthen 

 life by accelerating or retarding the moment of reproduction. 

 If, by means of a rich manure, we cause biennial plants to 

 fructify during the first year of their existence, they die that 

 same year. On the contrary, the mignonette is rendered ligneous 

 and long-lived by cutting its flowers before the formation of the 

 j seed. 1 



Insects themselves live much longer when they are prevented 

 from pairing. 



Death may be general or partial. This latter is frequent in 

 all organisms with a feeble physiological centralisation, in vegetals 

 and in many lower animals. It is even not uncommon in the mam- 

 mifers. Inversely, in these latter, the partial life of certain 

 elements, especially of the epitheliums, often continues after 

 general death, characterised by the cessation of the three pri- 

 mordial functions, circulation, respiration, and innervation. 



Death may ensue through simple old age, in consequence of an 

 extremely gradual slackening of the molecular movements of 

 nutrition. It then takes place without pain, without illness, 

 without agony, sometimes without consciousness, and may even 

 be accompanied by a certain feeling of comfort ; it is then the 

 eutlianasia of Plato. 



Pinel has observed that at the Salpetriere most of the nona- 

 genarian women died without any shock, and often in their sleep. 



Death is, in fact, only a final cessation of nutritive exchanges. 

 Every being, every anatomical element which ceases to assimilate 

 and disassimilate, returns consequently to the mineral world. 

 The materials which constituted it then undergo purely chemical 

 unfoldings, decompositions, and disaggregations. 



During the life of a complex organism, many of its histological 

 elements perish, without their death being in any way prejudicial 

 to the life of the whole. Sometimes the elements of certain tissues 

 become mutually compressed, and thus, by simple pressure, cause 

 the gradual disappearance of some of them. Sometimes the 

 1 De Candolle, Organographie Vegetale, t. II. 



