A NEW START IN PHYSIOLOGICAL RESEARCH.

(From a correspondent at Copenhagen)

     During the International Medical Conference held in Copenhagen in the summer of 1884, a paper read by the Rev. Malling Hansen, Principal of the Danish Institution for the Deaf and Dumb, was listened to with marked attention and interest. It gave the results of the daily weighings and measurements of height which he had carried on for nearly three years on the 130 pupils, 72 boys and 58 girls, of the institution, and demonstrated facts as to the development of the human body during the period of childhood that perfectly startled and astonished the assembled medical authorities, opening an entirely new field for investigation and reflection. Since then Mr. Hansen has continued his observations, and though he has yet a tremendous amount of work before him, he believes himself able to state now the outlines of the results he has obtained. Before entering upon these it may be proper to explain that the children are weighed four times daily, in batches of 20, in the morning, before dinner, after dinner and at bed time, and that each child is measured once a day. The scales and appliances used are ingeniously contrived, allowing the whole business to be finished in five to ten minutes, and sufficiently accurate to indicate even the smallest difference. The children have taken immensely to the thing; they are eager to perform their part, and all fingers are astir to repeat the numbers, rejoicing at every marked change.

     The common impression is, no doubt, that increase in the bulk and height of the human body during the years of growth progresses evenly all through the year. This is not so. Three distinct periods are marked out, and within them some 30 lesser waverings have been observed. As for bulk, the maximum period extends from August until December; the period of equipoise lasts from December until about the middle of April; and then follows the minimum period until August. The lasting increase of bulk or weight is all accumulated during the first stage; the period of equipoise adds to the body about a fourth of that increase, but this gain is almost entirely spent or lost again in the last period. The increase in height of the children shows the same division into periods, only in a different order. The maximum period of growth in height corresponds to the minimum period of increase in bulk, and vice versa. In September and October a child grows only a fifth of what it did in June and July. In other words, during a part of the year, autumn and beginning of winter, the child accumulates bulk, but the height is stationary; in the early summer the bulk remains nearly unchanged, but the vital force and the nourishment are expended to the benefit of height. While the body works for bulk, there is rest for the growth, and when the period of growth comes, the working for bulk is suspended.

     The human body has, consequently, the same distinctly-marked periods of development as the plants. Mr. Hansen has extended his daily measurements also to a number of trees in the garden of his institution, and has convinced himself, that here also a period of growth in length, as represented by the branches, twigs and tops alternates with another of increase in bulk – that is, in the circumference of the trunk, followed by a third period of equipoise and rest. In April and May the entire force was expended in the lengthening of the branches, while the thickness of the trunk remained stationary; all through May the most exact measurement failed to discover any increase of bulk. But in June until the middle of July, when the new twigs had been all formed, it was the trunk that absorbed the nourishment from the roots and bulged out. Then came the period of rest and inactivity.

     It was stated above that, within the three chief periods of the human (or rather the infantile) body, the observations had pointed out some 30 smaller waverings of more passing nature. The ordinary movement may be subjected to disturbances, a swifter or slower increase, sometimes even positive loss. These waverings prove to be subject to constant laws and independent of accidental or local influences; they return exactly in the same manner and present the same features. One constant relation can be pointed out between these waverings and the movements of temperature in the outer air. If the thermometer rises steadily through several days, the increase in weight also becomes greater, but not equally from day to day; the second day the increase becomes double, the third day three times as much, and so on, until there is a fall of the temperature. If it grows colder there is a decrease in weight (or a lesser increase), but again on the second day double, the third day three times as much, and so on, until a new change of temperature intervenes. The effect of the short periods of change in the thermometer is, consequently, just the contrary of that observed in the longer period. A higher temperature is favourable to increase in weight or bulk; a lower counteracts it, if considered singly; while the warmer seasons, spring and summer, put a stop to that form of growth, leaving it to autumn and winter to favour it.

     Mr. Hansen has not restricted himself to the set of pupils in the institution intrusted to his care. He has caused corresponding observations to be made also in several other places, where a number of children were subjected to the same regime and the same conditions of life. An orphan school in Copenhagen [1], another deaf-mute institution in Jutland [2], and a village school [3] have under his instructions carried out a series of investigations, for which a subvention has been granted out of public funds. The results obtained confirm in a most surprising manner his own. In the graphic representation of the observations the curves from the different fields of investigation follow each other very closely, mounting and descending under the evident influence of identical laws. He is still engaged upon his arduous task and working out the many different problems meeting him on his way. Physiologists will, however, hardly be inclined to accept all his facts or to subscribe to all his deductions. It is only right that they should judge for themselves, verify the observations, and submit the deductions from them to a careful trial. If it turns out that they are proved, then various conclusions of high importance for the hygienic treatment of children are to be drawn. At all events, Mr. Hansen may claim to have opened an entirely new and undoubtedly fertile field for exact physiological research.