were admitted for the first time to any hospital for the insane in New York state; one in 1,600 of the whole population or one in 1,000 if only those above the age of sixteen are considered. Here, then, is our problem in the prevention of insanity. Was it possible, by means at our command to have saved any of these unfortunates from becoming insane last year? Must an equal number, the population of a large town, be admitted next year, another 5,000 in 1912 and so on in the years to come? Are there facts at hand which point to practical measures of prevention or are the causes of mental disease so little understood or so deeply rooted that this sad toll of 5,000 new cases in a single state must be paid each year without hope of reducing it in the future?
Those who are responsible for the care of the insane in the various states are deeply impressed with the necessity of being able to give definite answers to these questions. In preventive medicine accurate knowledge must precede action and so statistics are being carefully gathered and analyzed in order that reliable information may not be wanting in this field of the prevention of disease. The New York State Lunacy Commission, which is charged with the care of nearly one fifth of all the insane in the United States, has recently adopted a greatly improved method of obtaining statistical data regarding new patients and already sufficient material is available to permit the accurate statement of some conditions which could be presented previously only in a general and rather unconvincing way. So, in this discussion of two preventable causes of insanity, it is worth while to examine the records of the 5,301 "first admissions" in New York state for the year which ended September 30, 1908.
At the very outset of any consideration of insanity, it is necessary to make it plain that we have to do not with one disease, manifesting itself in different ways, but with a number of diseases, differing very greatly from each other in many important respects. What is true of the causes or of the clinical characteristics of one mental disease may be entirely untrue of another. Various mental diseases, or "insanities" as it would be quite permissible to call them, are grouped together because of some similarity, and all these groups make up insanity as that term is generally used.
The mental diseases of one such group have the common characteristic of depending upon a preceding infectious disease. Permanent or transitory mental impairment may follow typhoid fever, influenza and some other acute, infectious diseases and it is obvious that these mental disorders are preventable in just the measure in which the diseases upon which they depend are preventable. The number of these cases is not large, and yet, when the cost of the needless prevalence of typhoid fever is estimated, these more remote effects should be considered.
