100 years ago

Among many other papers in the Proceedings of the Indiana Academy of Science, dated 1894, but only just received, is one by Mr. D. T. MacDougal, showing that various species of Cypripedium have an irritant action upon the human skin. It was found that when the leaves of C. spectabile were rubbed lightly upon the skin of the wrist, arm, face, or ear, the person experimented upon was usually “poisoned” in a degree corresponding to the manner of application, and in a time varying from ten to twelve hours. There could be no doubt about the unpleasant effects produced by the leaves, for Mr. MacDougal soon found that he could not obtain subjects willing to sacrifice their feelings upon the altar of scientific knowledge. ⃛ To ascertain whether the effect was due to the mechanical injury resulting from piercing the skin by the pointed hairs upon the leaves, or to the corrosive action of the secretion found on the outside of the globular tips of the glandular hairs ⃛ the hairs of each kind were taken from the leaf by means of a fine pair of forceps, and the tip pressed against the skin. Irritation was found to result from the contact of the glandular hair only.

From Nature 2 September 1897.

50 years ago

It is common knowledge that open coal fires radiate only a small fraction of the heat available from bituminous coal, most of the rest being carried up flues to the outside air. In many countries climatic conditions or the need for thrift enforce various means to avoid waste of fuel. Independent stoves are placed in living-rooms or heat is distributed throughout buildings by means of warm water or air propelled either mechanically or by gravitational action. To-day circumstances are compelling Britain increasingly to adopt similar methods. The growing use of closed stoves is a familiar example whereby 65 per cent of the heat of combustion can be distributed in a simple manner, at the cost of losing, wholly or partly, the heating by radiation from the glowing fuel. ⃛ The widespread construction of new houses offers advantages in such methods, advantages which are being taken.

From Nature 6 September 1947.