of death, and, if prolonged, becomes exhaustion, which, unrestored, goes on to extinction of faculty and structure. This immortal soul, then, if it be the guardian of every part of the body, must be supposed to be a perfect guardian, always equally vigilant and equally powerful. If this be so, how does it happen that, if you withhold food from a body of men for a couple of days, you will find the great majority of them laid up with a fever? The exciting cause of the fever was present, as well when the men were fed as when they were fasting—why did it take no effect upon the well-fed army, and attack only the famished? Can this be explained by the soul-theory? The soul needs neither meat nor drink; it is immaterial, immortal. Then it was not the soul that opened the gates of the citadel over which it is supposed to keep watch: who or what is it that plays traitor on such occasions? The reply to this question is, that the soul does not operate directly upon the animal frame, but, as Whytt expresses it, "through the intervention of something in the brain and nerves." This "something is what goes by the name of "the animal spirits," a term preserved in popular language, and still in constant use, as when we say we are in "low spirits," or "out of spirits." Although the term Animal Spirit was by no means new, yet at this period an attempt was made to give it a more rigorous signification; and the writings of the 17th and 18th century abound in definitions of what is to be understood by the expression. "The animal spirits are the quintessence of the blood and other juices; the vehicle of which is lymph and water extremely dessicated and moveable, and extremely attenuated by flowing through vessels which from large become gradually smaller, being rarified by heat with a subtle vapour. "The nervous fluid, or animal spirits, consists of phlegm or water, oil, animal salt, and earth, all highly attenuated and subtilized, and intimately mixed and incor

1

porated together." We may observe that the terms animal spirits and nervous fluid are used as synonomous. "It is evident," says Dr. Barry,2 "from the structure of the nerves, and from their being deprived of their influence when obstructed by a ligature or diseases, that the exercise of their function depends upon the motion of a nervous fluid or animal spirits through them." "This nervous fluid seems to be formed for more extensive uses than sensation and motion."

The celebrated Dr. Mead writes :-" This fluid, so far as we can discover by its effects, is a thin volatile liquor, of great force and elasticity; being, indeed, most probably, a quantity of the “mineral elastic matter," incorporated with fine parts of the blood, separated in the brain, and lodged in the fibres of the nerves. This is the instrument of muscular motion and sensation, and a great agent in secretions, and, indeed, in the whole business of the animal economy. By the universal elastic matter I understand the subtle and active substance diffused throughout the universe, which our great philosopher, Sir Isaac Newton, supposes to be the cause of the refraction and reflection of the rays of light, and of the vibrations by which light communicates heat to bodies, and which, readily pervading all bodies, produces many of their actions upon one another. This is the nature of the animal spirits."3 Between the idea that the animal spirits were a quintessence evaporated by the heat of the body from all its parts, and therefore confining, in a spiritual or ghostly form, all the elements which the body contained; and this notion of the animal spirits being a portion of the ether of the universe, the contrast is great, and warns us not to confound all the so-called vitalists in one category.

1 Dr. Malcolm Fleming on the Nature of the Nervous Fluid, p. 24.

2 A Treatise on Digestion, by Dr.

Barry, p. 157.

3 A Mechanical Account of Poisons, by Dr. Mead.

Let us now consider how this hypothesis of Stahl's stands related to pathology and therapeutics. One important fact, well-nigh forgotten by the chemists, was brought into prominence by Stahl, viz., that man was a spirit, and, as such, subject to many disorders from which the lower animals are free; and that, in dealing with man as a subject of experiment or investigation, we shall be led into certain error if we neglect the spiritual elements of his constitution. But, this fact admitted, still we want to know how the spirit acts in deranging the body. We find this question discussed by Stahl's disciples. Perry' tells us, that the whole tribe of nervous diseases arises from what he calls distemperature of the animal spirits. Let us observe that most writers of his school, although they so far accept Stahl's notion of the soul as the chief source of life, yet, when they come to work the problems of pathology, transform the soul, or the immaterial and undying part of man, into a material spirit. Thus Perry speaks of the animal spirits being material, although subtle, and being subject to depravation and alterations of various kinds, and of the great indication for the cure of diseases in which they are implicated being to strengthen them. To strengthen the animal spirits! Here is a new theory of treatment. differs from the doctrine of humours taught by Hippocrates and Galen; it differs from the doctrine of specifics taught by Sydenham, and from the doctrine of the chemists. It is the beginning of a great change in the practice of the art of medicine; for by the term "to strengthen the animal spirits," is really meant to stimulate them; to excite them to make a greater effort to resist or overcome the evil forces in the system. This doctrine is the unavowed parent of subsequent systems. If Stahl is right, that the spiritual principle presiding over every specification of the frame is the source of all vital motions, and if the

A Treatise on Disease, by Dr. C. Perry, Vol. I., p. 50.

It

languid performance of this all-important office gives rise to imperfect and disordered action, then it follows that the great secret of cure will consist in stimulating the animal spirits or nervous fluid-for the expressions are used as identical--so that it may act with more force, and set right the disorder, wherever it is. Out of Stahl's theory, then, we naturally glide into the doctrine of regarding enfeebled action of the nervous system as the great source of disease, and the administration of stimulants as the great corresponding remedy. It was reserved for another generation to work out the principles enunciated by Stahl to their natural and logical development. For himself, he accepted the traditional doctrine of accumulation and stagnation of blood, requiring the employment of blood-letting and evacuant remedies for their removal. He set his face against the use of Cinchona bark as attended with mischievous consequences, and only acting as an astringent in suppressing but not curing ague. Although he was thus blind to the merits of the great specific medicine of his day, he was in the habit, as well as Hoffmann, of selling various secret medicines; among which, according to Sprengel, who cites his authorities for the statement, were "socalled balsamic pills, made of aloes, veratrum, and bitter extract," which he professed to be good in almost all diseases; also a stomach powder; and both of these were held. in very general estimation. He had also his own peculiar styptic, which Goetz suspects was nothing but refined spirits of wine.1

This fact, for as such we may accept it, gives a shock to the notions of the present day. For two of the most celebrated physicians and teachers of their age to sell secret medicines, and not to lose caste by doing so, shows that

1 Gründlicher Bericht von der balsamischen Blut-reinigend-und-comfortirenden Pillen, wie auch, auf sonderbares Verlangen, von den rothen

fluss-magen-und-stein Pulvers, zuverlassiger sonderbaren Wirkung und rechten Gebrauch. Halle, 1716. Sprengel, Vol. V., p. 333.

as it is now.

such a proceeding was not regarded in the same light then Indeed, at a considerably later date, we find men of good standing publishing cases cured by remedies the name of which they concealed. For example, in the year 1745, Dr. Cromwell Mortimer, a member of the Royal College of Physicians, and Corresponding Member of the Royal Academy of Science of Paris, dedicated to the King of Britain of that period, George II., a work entitled, "Address to the Public, containing Narratives of Certain Chemical Remedies in most Diseases." This book is full of cases of cures effected by his secret remedies. It is plain, from passages in Sydenham, that he was sorely tempted to do so too; and in referring to the triumph of his virtue over his cupidity, he gives as the reason the broad ground of preferring the advantage of mankind to his own private profit a reason which, if applied to analogous cases, would do away both with the law of patents and of copyrights. Probably the true reason why secret remedies are held in such disrepute is, that they are for the most part pure impositions; and, having become disreputable, no man of respectable character will have anything to do with them. But this triumph of respectability has not been attained till this the nineteenth century. It did not exist, or but feebly, in the seventeenth and eighteenth, and in forming a judgment upon any case, we must take the conditions of time and place into consideration, if we wish to avoid the most absurd and unjust opinion in reference to its morality, or rather in reference to the morality of the person who performs the act.

Frederick Hoffmann was born at Halle, where his ancestors had for two centuries practised the medical profession, in 1660, the same year as his great colleague and rival Ernest Stahl. He showed at an early age a decided predilection for mathematics, and even before he entered the University of Jena, where he took his degree of Doctor