PREFACE. 7 



nature (and there are at present many with whom I am not 

 to be placed in comparison), being stimulated by this first essay, 

 will project and carry out a much more perfect system ; to me 

 it will be a matter of satisfaction that I had the honour of 

 affording the first ideas ; and if I might flatter myself that such 

 an one would also publish a special pathology of the proper 

 animal nature, according to these principles of a special phy- 

 siology, I should certainly think myself fortunate in having laid 

 the foundation for so great an improvement of our art. Any 

 one who is acquainted with the present condition of medical 

 science, and has at all attempted to remedy the striking defects 

 in the theory of proper animal nature, must be aware it was 

 necessary to any degree of progress that these first steps should 

 be taken. 



I will now briefly describe the plan of my work. 

 The primary seat of the animal forces is in the so-called 

 proper animal machines, namely, the brain with its animal spirits, 

 together with the nerves, through which the latter are com- 

 municated to the mechanical machines. I originally intended 

 to have given a general division, containing a general account 

 of the animal machines, and their structure and moving forces, 

 in which I should have included an anatomical description of 

 the brain and nerves ; but I determined to omit this part, so 

 as not with useless prolixity to extend a simple sketch, inas- 

 much as this description of the animal machines is already to 

 be found as complete as possible in the fourth volume of 

 Haller's larger work on Physiology, .and 1 have nothing to add 

 to it. I have, however, made extracts from, and given reference 

 to, the most indisputable statements with reference to the 

 animal machines and properties (most of which will be noticed 

 in the following pages), and thus originated the following plan 

 of a physiology of the proper animal nature of animal bodies. 



Animal nature is the aggregate of the proper animal forces, 

 and the science of these, uncomplicated, is the physiology of 

 animal nature. All animal forces act, when untrammelled, either 

 necessarily in connection with the mind of the animal, or not ; 

 and thus the science is divided into two great divisions. The 

 first treats of the animal nature in its connection with mind, 

 that is, in other words, with reference to the animal-sentient 



