skin excluded, but also that of the more superficial layers of the subcutaneous tissues, and it shows that they are endowed with sensibility at a considerable depth.
Several introspective observations were made on the character of the sensations of deep touch. On one occasion, H. recorded that without careful attention, no difference in quality would have been noticed between touches produced by pressure on the anæsthetic and normal areas. Pressure with the head of a pin on the normal skin produced a tactile sensation, together with sensations of slight cold and of hair-stimulation. On the affected area, the latter elements were no longer present, but the fundamental quality of the sensation seemed to remain the same, so that when the head of the pin was passed across the border separating the normal and affected areas, a considerable effort of attention was necessary to detect when the change occurred. The differences in quality were of such a kind that it is very improbable they would be noticed by any but a trained observer. On a later occasion, observations were made by stimulating the normal right hand covered with a thin rubber glove, when H. noted that the quality of the touches resembled that experienced from the abnormal area.
The most extended observations were made on the back of the affected hand, because of the rapidity with which sensation began to return to the skin of the forearm. But during the short time at our disposal, the anæsthetic parts of the forearm were found to behave exactly in the same way as the insensitive area on the dorsum of the hand.
In conclusion, there is no doubt that the back of the hand was so sensitive to contact, that most observers would have said the sensation of touch was unaffected.
(2) Roughness.
One of the most striking features of a part endowed with deep sensibility is the ease with which roughness can be appreciated.
The utility of Graham Brown's æsthesiometer depends on our power of appreciating roughness, when small cylinders are made to project for a measurable distance from a smooth metal surface. When these projections can be perceived, the sensation is one as if the part was "raked." It was found that, in this respect, the affected parts of the left hand were in no way inferior to similar parts of the right hand.
Thus on June 7 the following readings were obtained:—
