MEDICINE. 



757 



for the purposes of life, by a process resembling 

 secretion. Darwin divides diseases into four great 

 classes depending upon certain functions of the sen- 

 surial power, which are irritation, sensation, volition, 

 and association. 



One of the latest train of medical reasoning, or 

 system of medicine, which has been proposed, is that 

 railed the doctrine of plethora, and which we shall 

 now attempt to describe. In this all the derange- 

 ments of the animal economy are attributed to gene- 

 ral or partial fulness of the blood-vessels or plethora. 

 This system is founded more upon the results of prac- 

 tical experience than from any imaginary views of the 

 nature of the animal economy. The great extent to 

 which the system of depletion has been carried, first 

 by Dr Rush and other practitioners in America and 

 the West Indies, and latterly by others in different 

 parts of Europe, has had a very powerful effect upon 

 medical opinions on all subjects, and lias tended to 

 reduce the whole of the practice of medicine to little 

 more than a succession of evacuations, or an altera- 

 tion in the different methods of abstracting the fluids 

 from the human body. By this means a most bene- 

 ficial effect has been produced both in the theory and 

 practice of physic. The work in which this doctrine 

 is presented in the most methodical and connected 

 form, is written by Dr Parry of Bath, and entitled 

 " Elements of Pathology ;" and the points he at- 

 tempts to illustrate and establish are these : That 

 the system of the blood-vessels is that which is most 

 frequently deranged, and from which nearly all dis- 

 eases originate. That partly from the natural con- 

 stitution of the body, partly from the present acquired 

 habits of civilized society, these derangements gene- 

 rally proceed, in the first instance, from an excess in 

 the quantity, or the moving force of the blood: added 

 to which, that our blood-vessels are peculiarly liable 

 to a state of local plethora, or fulness a state of parts 

 which may occur even when there is a general deficien- 

 cy in the quantity of the fluids. That this plethora may 

 have its origin from two distinct causes ; either from 

 the increased force of the heart, or from the resist- 

 ance of the vessels but that, although the mechanical 

 effect of these causes be nearly the same, and the 

 mode of treatment be also in a great measure similar, 

 yet that the state of the vital powers of the system, 

 or at least of the part affected, are totally opposite to 

 eacli other. Lastly, Dr Parry endeavours to prove 

 that the affections of the nervous system are entirely 

 secondary and subservient, and that these likewise 

 originate from an excessive determination of the 

 blood to the substance of the nerves themselves, 

 and that the distinction between diseases arises prin- 

 cipally from the parts that are affected ; and that the 

 character of their symptoms is determined, either by 

 the particular structure of the organ, by the nature 

 of the cause producing the disease, or by the peculiar 

 habits or constitution of the individual. 



For the newest systems, as the homoeopathic system 

 of Hahnemann (see Homoeopathy), or that of M. 

 Broussais, a Frenchman, who strives to trace all 

 diseases to inflammation of the bowels, we must refer 

 to the publications of the authors, and to the medical 

 periodicals. See Kurt Sprengel's Geschichte der 

 Arzneikunde (third edition, Halle, 5 volumes, 1827; 

 translated into French, Paris, 1816) ; J. F. K. 

 Hecker's Geschichte der Heilkunde (Berlin, 1822, 

 vol. 1) ; Hamilton's History of Medicine (London, 

 1831, 2 vols., 8vo, &c.). 



The various medical sciences, or those closely con- 

 nected with them, and more or less requisite for a 

 thorough knowledge of medicine, may be thus 

 enumerated : the whole range of natural sciences, 

 as zoology (including comparative anatomy and physi- 

 ology, mineralogy, geology, botany, natural philoso- 



phy, chemistry, &c. : psychology, which teaches the 

 various phenomena of soul and mind : anatomy, 

 which teaches the form and situation of tiie organs 

 by the examination of dead bodies, and is divided 

 into osteology, treating of the bones ; syndesmology, 

 of the ligaments ; mymogy, of the muscles ; splanch- 

 nology, of the intestines ; angiology, of the vessels ; 

 neurology, of the nerves ; and adenology, of the 

 glands : organic physics, treating of the mechanical 

 operations of the human body, the power, gravity, &c., 

 of its parts : physiology, which treats of all the pheno- 

 mena of life in connexion.* Such is the basis of all 

 those branches of science which may be more particu 

 larly called medical, and which we will now enume- 

 rate. The science of health, that is, of that in which 

 it consists, its conditions, and its signs, is called 

 hygiene, or as far as it relates to the regulation of the 

 diet, diaetetics. Pathology, on the other hand, is the 

 science of disease, of that in which it consists, its 

 origin, &c. Nosology treats of the various sorts of 

 diseases, their origin and symptoms, and strives to 

 arrange diseases into one whole. Pathological 

 anatomy teaches the mechanical alterations and 

 changes of structure. Semiotics teaches to infer from 

 the various symptoms, the nature of the disease ; dia- 

 gnostics, to distinguish the symptoms of different 

 diseases ; and prognostics, to infer, from the past and 

 present state of a disease, its future course. Thera- 

 peutics is the science of the cure of diseases, often 

 divided into general, treating of the subject of 

 cure in general, its character, &c., and special, of 

 the cures of the particular diseases. Surgery treats 

 of mechanical injuries, and the mode of relieving 

 diseases and derangements by mechanical means. 

 Obstetrics treats of the modes of facilitating delivery. 

 Materia medica is the science of medicines, their ex- 

 ternal appearance, history, and effects on the human 

 organization. Pharmacy teaches how to preserve 

 drugs, &c., and to mix medicines. Clinics (q. v.), or 

 medical practice, applies the results of all these 

 sciences to real cases. We should mention, in this 

 connexion, the history and literature of medicine, the 

 history of diseases, a very interesting branch, political 

 medicine, which is divided into medical police and 

 forensic medicine, that branch which enables the 

 physician to give to courts and other legal authorities 

 proper explanations in regard to personal injuries, 

 particular appearances of the body, &c.,as whether a 

 wound was mortal, how inflicted, whether a child was 

 dead before born, &c. In many countries, physicians 

 are appointed by the government for this purpose. 

 We must last mention midwifery, as taught, in many 

 countries, to women, who make a regular study and 

 business of it. A student of medicine ought to be 

 well versed in the two learned languages, and cannot 

 dispense with a respectable knowledge of English, 

 French, German, and Italian. Among the works 

 which treat of medicine at large are Dictionnaire tics 

 Sciences Medicates par une Societe de Medecins ct 

 Chirurgiens (Paris, Panckoucke, containing 60 vols., 

 1812 to 1822), and Journal complcmentairc du Diet, 

 des Sciences Med. (from 1818 to 1824, 17 vols., still 

 continued) ; Encyklop. IVorlerbuch der Medicin 

 fVissenschaften (edited by the professors of the 

 medical faculty at Berlin Grafe, Hufeland, Link, 

 Kudolphi, von Siebold, Berlin, vol. i., 1827) ; also 

 Good's Book of Medicine. 



Medical Geography is geography applied to medi- 

 cine, treating all the subjects of geography which 

 have any influence upon the health, the bodily struc- 

 ture, activity of mind, and the diseases of men. It is 



* Some add here, anthropochemio or the chemistry of tlio 

 human body, the chemical composition of nil its parts a ino>t 

 important branch, hut usually treated under general chemistry 



