I will only corroborate here a remark already made in the same work, upon the extreme frequency of pulmonary congestions in the last moments of life. As the lungs alone receive the whole blood of the body, when their forces are weakened, the blood stagnates and accumulates in them; so that according to the state of their forces in the last moments, and the disease, these organs will be more or less heavy, and more or less full of blood. We hardly find them twice in the same state. All subjects that die in pain have these congestions. Thus compare the lungs of dead bodies in our dissecting rooms, with those of animals killed in slaughter-houses; they are entirely different. The organization is almost always concealed in the first by the fluids that crowd them. We cannot study this organization well except in subjects that have died of hemorrhage or syncope. In most others, it is impossible to distinguish any thing. Hence no doubt the reason that we know as yet so little of the intimate structure of this important viscus, as the description I shall give of it will, I hope, prove. I have shown elsewhere how we can at will accumulate a greater or less quantity of blood in the lungs of an animal, by the way in which we kill him. No other organ in the economy exhibits these extreme varieties of congestion at the moment of death, in so evident a manner at least, because no one is a centre of circulation, like the lungs; the liver even is not an exception, as I have observed. In this respect, those who open dead bodies, and examine the state of the lungs, should carefully distinguish the congestion that arises from the disease, from that which may be perhaps the effect of the interruption of the circulation in the last moments. I suppose two affections of the chest exactly similar in their nature, duration and the two subjects they attack; that syncope terminates the life of one of them; that that of the other is closed after long distress, in which there is what is called the rattles; the lungs of the second will certainly weigh much more than those of the first. It is very probable that during life, the lungs are in very different degrees of congestion. We know that most chronic diseases of this organ occasion, when the patients take rather violent exercise, a sense of suffocation, oppression, &c. which appear to be owing only to the superabundance of blood, which, not being able to pass through this viscus as fast as it is sent there, is stopt, and checks the entrance and exit of the air. It is only the diseases of the lungs and heart that are accompanied constantly with these oppressions, and sense of suffocation. This is seen in this last organ in aneurisms, sometimes in ossifications, &c. EXHALANT SYSTEM. Exhalation and secretion are two functions, analogous in this, that both of them separate from the blood fluids differing from it, and pour them upon surfaces where they serve different uses. But the following are their differences.