2 54 Mayow 



the nerves originating in it ; whence it comes about 

 that if the head of such animals is removed, the 

 influx of animal spirits into the spinal marrow is 

 altogether shut off, so that the parts of the decapi- 

 tated body at once collapse and are deprived of 

 animal motion. 



But in less perfect animals, such as insects, whose 

 cut-off parts live, the animal spirits are primarily and 

 immediately prepared, not only in the brain but also 

 in the protuberances of the spinal marrow, as it 

 were in so many cerebelli extended through the 

 whole length of the spinal marrow, or rather they are 

 stored as in suitable repositories ; and hence it comes 

 to pass that in the cut-off portions of insects, the 

 animal spirits are supplied, for keeping up to some 

 extent life and motion, from the small piece of spinal 

 marrow connected with each portion. 



But that the animal spirits should be brought into 

 the spinal marrow of insects, it is most necessary that 

 some spiracula or bronchiae should be, as is the case, 

 continued into it, so that nitro-aerial particles, of 

 which animal spirits consist, should by their means be 

 carried into the spinal marrow. Hence, if any of the 

 said spiracula be smeared with oil, the neighbouring 

 parts, inasmuch as they are deprived of nitro-aerial 

 particles and of animal spirits, at once become para- 

 lysed, the remaining parts being meantime healthy ; 

 while yet in perfect animals the nitro-aerial particles 

 are introduced into the blood only through the lungs, 

 and then, by the heart's pulsation and the flow of 

 the blood, are carried to the brain and thence to 

 its spinal appendix. Hence it happens that if the 

 trachea is obstructed, and inspiration suppressed, or if 

 the motion of the heart and of the blood stops, or 

 even if the brain is disordered, the nitro-aerial particles 



