Class IV. i. 4. 1. OF ASSOCIATION, 395 



ORDO I. 



Increased AJJbciate Motions, 



GENUS IV. 



Catenated ivith External Influences. 



SPECIES. 



1 . Vita ovi. Life of an egg. The eggs of fowls were (hewn 

 by Mr. J. Hunter to refill the freezing procefs in their living 

 ftate more powerfully than "when they were killed by having the 

 yolk and white (hook together. Philof. Tranf. It may be aik- 

 ed, does the heat during the incubation of eggs acft as a ftimulus 

 exciting the living principle into activity ? Or does it act fim- 

 ply as a caufa fine qua non, as an influence, which penetrating 

 the mafs, removes the panicles of it to a greater diftance from 

 each other, fo as to allow their movement over each other, in the 

 fame manner as heat is conceived, to produce the fluidity of wa- 

 ter •, not by ftimulus, but by its penetrating influence ? Or may 

 elementary heat in its uncombined ftate be fuppofed to act only 

 as an influence neceflary to life in its natural quantity ; whence 

 torpor and death follow the eduction of it from the body ; but 

 in its increafed ftate above what is natural, or ufual, that it acts 

 as a ftimulus ; which we have a fenfe to perceive ; and which 

 excites many parts of the fyftem into unnatural action ? See 

 ClafsIV. 1. 1. C. 



2. Vita hiemi-dormientium. The torpor of infects, and birds, 

 and quadrupeds, during the cold feafon, has been called fleep j 

 but I fuppofe it muft differ very much from that ftate of animal 

 life, fince not only all voluntary power is fufpended, but fenfa- 

 tion and vafcular motion have ceaied, and can only be reftored 

 by the influence of heat. There have been related inftances of 

 fnails, which have recovered life and motion on being put into 

 water after having experienced many years of torpidity, or ap- 

 parent death, in the cabinets of the curious. Here the water as 

 well as the heat are required not only as a ftimulus, but as a 

 caufa fine qua non of fluidity and motion, and confequent life. 



3. Pullulatio arborum. The annual revivefcence of the buds 

 of trees feems not only to be owing to the influence of the re- 

 turning warmth of the fpring, but alfo to be catenated with fo- 

 lar gravitation ; becaufe feeds and roots and buds, which are 

 analogous to the eggs of animals, put forth their (hoots by a lefs 



quantity 



