INTRODUCTION. XXI 



peculiarities, which may be ascertained by their dis- 

 eases, and by the influence of different agents, as heat, 

 air, water, acids, alkalis, neutral salts, and putrefaction. 

 Each tissue has its particular strength, and its particular 

 mode of sensibility, upon which repose all its vital phe- 

 nomena, and the blood is but a common reservoir, where 

 each chooses what is in relation to itself. An example, 

 however, will serve better for illustrating these several 

 points. The stomach is composed of four laminae, one 

 is serous, another muscular, a third cellular, and a fourth 

 mucous. Each of these laminse has its appropriate sen- 

 sibilities and mode of life, which may cause it to be dis- 

 eased, while all the others are healthy. Peritoneal in- 

 flammation may invade the first, the cramps of colic the 

 second or muscular, the infiltration of dropsy the third 

 or cellular, and dyspepsia the fourth or mucous. 



It thus happens, that the diversity of the tissue of an 

 affected organ modifies the symptoms of its diseases, and 

 especially their duration. Hence, nothing is more vague 

 in medicine, in regard to duration, than the terms chronic 

 and acute. An inflammation in one tissue will go na- 

 turally through its stages in a few days, as, for exam- 

 ple, in the skin, cellular substance, mucous membranes; 

 while in the bones and ligaments, on a natural progress 

 being also observed, weeks and months are required for 

 its accomplishment. It is evident, therefore, that a 

 time which is chronic in the first three tissues, is acute 

 in the lagt two. 



A chemical analysis of the body demonstrates only a 

 few elementary principles; and they are varied in their 

 combinations by a greater or less proportion of one or 

 the other. Calcareous matter, the neutral salts, carbon, 

 hydrogen, oxygen, nitrogen, sulphur, iron, wrought up 

 by the powers of animalization into gelatine, albumen, 

 and fibrine, which again are elaborated into the fibrous 

 and laminated tissue, constitute about the sum total of 



