tent agency, and accompanied by such general remarks and deductions as they might suggest, in connection with the sanitary reports of the General Board of Health. To ascertain how far our plan was practical, and might be approved by competent judges, we addressed a communication to Wm. Cranch Bond, Esq., of the Cambridge Observatory. His communication appears in the appendix, together with an extract from the report of the Royal Observatory at Greenwich.

After the above was written, the legislature passed the following Resolve relating to meteorological observations."

"Resolved, That his excellency the governor be authorized and requested to fix upon suitable stations, not exceeding twelve in number, in which shall be included the three Normal Schools and the three Colleges in this Commonwealth, where shall be deposited the instruments necessary for making systematic observations in meteorology, according to the plan recommended by the Smithsonian Institute, at an expense not exceeding one hundred dollars for each station, to be defrayed from the school fund, and that he be authorized to draw his warrant therefor accordingly."

If suitable agents are appointed under this resolve, our recommendation can be fully carried out without further legislation.

XVI. WE RECOMMEND that, as far as practicable, there be used in all sanitary investigations and regulations, a uniform nomenclature for the causes of death, and for the causes of disease.

In making a survey of different places, or different articles, it is proper that uniform names should be given to measures and weights; and that uniform instruments should be used. In a sanitary survey the causes of death and the causes of disease will be the principal objects of investigation; and it is expedient, and even necessary, that such names should be given to each as have a definite meaning and can be universally applied. They are the measures and weights, the instruments by which the computations are to be made. Without such a uni-、 form standard of comparison no just conclusions can be drawn. It would be equally proper to use Fahrenheit's thermometer in one place and Reaumur's in another, to estimate the compar

ative temperature of the atmosphere; or two different kinds of instruments as measures of weight and length, in other matters, as to use one name or classification of causes of death, or causes of disease, in one place, and a different name or classification for the same causes in another., Hence the reason for the above recommendation in a plan for a sanitary survey of the State will be apparent.

A report containing a nomenclature and classification of the causes of death was drawn up, and adopted by the National Medical Convention in 1847. Extracts from a revised copy, approved by the Massachusetts Medical Society, are inserted in the appendix. We hope that the directions and suggestions they contain will be carefully observed by all physicians, and others concerned in carrying the sanitary laws of the State into effect.

The causes of disease, in all sanitary inquiries, deserve equal, if not greater attention, than disease itself. They have been differently classified and named by different authors. By some they have been divided into external or extrinsic, and internal or intrinsic; by others, into principal and accessory; and into remote and proximate; and in other ways. Copland, (Diction. Vol. I, page 645,) divides them into four classes,predisposing, exciting, specific, and determining or consecutive causes; and makes several sub-classes under each. Bigelow and Holmes (Marshall Hall's Practice of Medicine, Am. Ed. pp. 67-83) divide them into general and specific causes; and subdivide the former into predisposing and exciting, and the latter into contagious and non-contagious. Williams (Principles of Medicine, p. 23, Am. Ed.) divides them into predisposing and exciting causes; and makes, a subdivision of the second into cognisable and non-cognisable agents. None of these classifications, however well they may be adapted for professional use, seem well designed for general sanitary purposes. They are not sufficiently clear to be generally understood and practically useful. Bigelow and Holmes say, this classification "must be considered convenient rather than strictly philosophical." Even Williams himself says that "these divisions of causes are rather conventional and convenient than natural and philosoph

ical;" and every one who may examine them will probably come to the same conclusion. It is easy to perceive that one may be a predisposing cause in one case and an exciting cause in another; and vice versa, according to circumstances.

As in the nomenclature and classification of causes of death it has been found difficult to make one which shall be universally approved, so in classifying the causes of disease the same. difficulty may occur. Yet we deem it proper to recommend that all causes of disease should be divided into three general classes:-1. ATMOSPHERIC; 2. LOCAL; and 3. PERSONAL.

I. Under ATMOSPHERIC CAUSES, we would include those to which all persons in a country or district, in circumstances in all respects alike, are equally exposed. Sub-classes; 1. Climate; 2. Seasons; 3. Winds and weather; 4. Electricity; 5. Atmospheric weight, temperature, moisture, and composition; 6. Malaria; 7. Unknown conditions of the atmosphere. What have been called epidemic causes of disease come under these classes.

II. Under LOCAL CAUSES We would include those to which persons living in a particular neighborhood or dwelling house, in circumstances in all respects alike, are equally exposed. Sub-classes; 1. Elevation or depression of situation; 2. Deficiency or impurity of water; 3. Defective sewerage, drainage, and surface cleansing; 4. Animal and vegetable effluvia; 5. Confined and corrupted air; 6. Irregular and imperfect supply of light and heat; 7. Filthy or damp habitations; 8. Existing contagious diseases; 9. Unknown local causes. What have been called endemic causes of diseases come under these classes. We would, however, restrict them to a particular house, street, or neighborhood. When the influence spreads over a whole town or district, it becomes an atmospheric cause. III. Under PERSONAL CAUSES We would include those which originate with the person alone, independent of atmospheric or local causes. Sub-classes; 1. Hereditary constitution, organization or vitality; 2. Acquired constitution, organization or vitality; 3. Deficiency and excess in quantity, and improper kind of food; 4. Improper quantity and kind of clothing; 5. Occupa tions and habits; 6. Excessive physical exertion; 7. Excessive

mental action; 8. Alienation of mind; 9. Exposure; 10. Personal contact with a diseased person, virus or poison; 11. Violence and accidents; 12. Unknown personal causes.

Atmospheric, and local, and personal contagion may exist as causes of disease. Some diseases can be communicated only by actual contact with another person, or with the poison of the disease of the person; as itch, syphilis, necusia, &c. This is personal contagion. Others may be communicated either by contact with the air of the locality where the diseased person is or has been; as small-pox, measles, &c.; or with the poisonous emanations from decomposing animal or vegetable matters, or from other substances; this is local contagion. Others may be communicated by contact with the atmosphere while in a peculiar condition; as influenza, dysentery, cholera, &c. ; this is atmospheric contagion. All these kinds of contagion may exist, to a greater or less extent, and press upon us with greater or less power.

Atmospheric contagion is generally harmless unless attracted by local causes; and if atmospheric and local contagion be combined, it may be successfully resisted by a person fortified with sufficient personal vitality. There seems to be a chemical affinity between the epidemic constitution of the atmosphere, and filth and unfavorable local circumstances, which combine readily with the conditions of the particular persons whom it affects; and the combination gathers together the poison of disease in so great intensity that few who are exposed are able to resist it. Under such circumstances those who are healthy, and live temperately and regularly, often escape ; while the debilitated, intemperate, irregular livers, generally become victims! An illustration of this fact may be drawn from the history of that terrible disease, the Asiatic Cholera,-a disease which derives its terrific power chiefly or entirely from the accessory or accompanying circumstances which attend it. It bounds over habitation after habitation where cleanliness abides; and generally leaves unharmed those inmates who have preserv ed and improved their natural constitutions: whilst it alights near some congenial abode of filth or impurity, and finds sub

jects prepared for easy conquest by previous violations of the laws of health and life.

Dr. Mitchell, of Philadelphia, suggests the "cryptogamous " origin of epidemic diseases, and some English periodicals have speculated on the alleged discovery of sporules or organic cells, as causes of cholera. But it would seem difficult to ascertain the cause of these causes, even if they are causes, (which is yet to be proved,) without looking to some peculiar antecedent atmospheric condition to account for their production.

If this were the proper place it would be easy to show that this classification is more natural, simple, comprehensive, and philosophical, and better adapted to general practical purposes, than the classifications in general use. The extracts we have already given under our XVth recommendation, prove that a similar distinction has been indirectly acknowleged by the best medical writers. Many other similar quotations might be given. We are aware that it may sometimes be difficult exactly to draw the line which separates atmospheric from local causes, though not, as seems to us, for general purposes, in the restricted sense in which we use the terms. It seems to us that any ætiologist would have more difficulty in drawing definite lines to separate contagious from infectious, or predisposing from exciting, or cognizable from non-cognizable causes of disease.

XVII. WE RECOMMEND that, in laying out new towns and villages, and in extending those already laid out, ample provision be made for a supply, in purity and abundance, of light, air, and water; for drainage and sewerage, for paving, and for cleanliness.

It is a remarkable fact, that nearly the whole increase of the population of Massachusetts, during the last twenty years, is to be found in cities and villages, and not in the rural districts. The tendency of our people seems to be towards social concentration. And it is well to inquire what will probably be the consequences of these central tendencies; and how, if evils are likely to arise from this cause, they may be avoided. It has been ascertained that the inhabitants of densely populated places generally deteriorate in vitality; and that, in the