cH.ii.] PRINCIPAL GENERA OF EXISTING ANIMALS. 319 



the same connection, and from the same external impressions, 

 as before decapitation. A single series of experiments, having 

 such results, would be sufficient to refute the proposition, that 

 to every animal life a body, soul, and brain are necessary. Yet 

 nature presents millions of such examples : the whole creation, 

 nay, every drop of water is full of them ; numerous genera of 

 animals exhibit no trace of a brain, or its analogues ; all their 

 acts, as in sentient animals, can be simply nerve-actions ; their 

 bodies are so constructed, that these acts can take place with- 

 out any co-operation of a conceptive force. Their souls must 

 be extended, and be everywhere present in their bodies, since 

 polypes may be cut into pieces, and each piece becomes a new 

 animal. Contrary to all analogy, there must be consciousness 

 in various parts of their organism, or they must consist of many 

 souls. How opposed is all this to sound theory and to com- 

 mon sense ! 



iv. Because, although some trace of a brain, or its analogue, 

 be found in animals, as in worms, snails, crabs, spiders, mites, 

 caterpillars, lice, ants, fleas, bees, and other insects and worms, 

 no indications of animal-sentient force can be detected in them. 

 In none of the animals undoubtedly sentient is the brain ever 

 the organ of the animal- sentient forces only; but it is endowed 

 also with the vis nervosa necessary to all animal life, even of an 

 insentient animal, since to it belongs the function of separating 

 the vital spirits from the blood, and distributing them to all 

 parts of the nervous system, for without these the mere vis 

 nervosa cannot act in any animal (21, 22). It is true, that this 

 is only the function of the cortical substance of the brain (159, 

 374) ; but who has proved that in the animals in question, the 

 brain consists of any other than this cortical substance ? More- 

 over it is probable, that the medullary substance of the brain, 

 even in sentient animals, possesses the vis nervosa, in virtue of 

 which, like the ganglia and spinal cord, it reflects external im- 

 pressions, receives non-conceptional internal impressions, and 

 by means of both moves the mechanical machines (373). It is 

 extremely probable, that the structure considered to be brain 

 in these animals is either only cortical substance, or only a 

 general ganglion, — an addition to the spinal cord, in which the 

 vital spirits are separated from the blood, and thence trans- 

 mitted through all the nerves ; in which also, as in the spinal 



