390 EXCRETION. 



reported instances which have not been subjected to proper investigation. One of these 

 cases is reported in Virchow's Archiv, for April, 1866, by Dr. Landois, as occurring under 

 the observation of himself and Dr. Lohmer. In this case, the blanching of the hair oc- 

 curred in a hospital in a single night, while the patient was under the daily observation 

 of the visiting physician. As this is one of the few well-authenticated instances of sudden 

 blanching of the hair, we shall give, in a few words, its essential particulars : 



The patient, a compositor, thirty-four years of age, with light hair and blue eyes, was 

 admitted into the hospital, July 9, 1865, suffering apparently from an acute attack of 

 delirium tremens. A marked peculiarity in the disease was excessive terror when any 

 person approached the patient. He slept for twelve hours on the night 'of the llth 

 of July, after taking thirty drops of laudanum. Up to this time nothing unusual had 

 been observed with regard to the hair. On the morning of July 12th, it was evident to 

 the medical attendants and all who saw the patient that the hair of the head and beard 

 had become gray. This fact was also remarked by the friends who visited the patient; 

 and he himself called for a mirror and remarked the change with intense astonishment. 

 The patient continued in the hospital until September Vtb, when he was discharged, the 

 hair remaining gray. An interesting point connected with this case is the fact that the 

 hairs were submitted to careful microscopical examination. The white hairs were found 

 to contain a great number of air-globules in the medulla and in the cortical substance, 

 but the pigment was everywhere preserved. The presence of air gave the hairs a dark 

 appearance by transmitted light and a white appearance by reflected light. Dr. Landois 

 quotes, in this connection, instances of blanching of the hair, in which each hair pre- 

 sented alternate rings of a white and a brown color. Another very curious case of this 

 kind was lately reported to the Royal Society by Mr. Erasmus Wilson. In this case, the 

 white portions presented, on microscopical examination, great bubbles of air ; but there 

 was no diminution in the quantity of pigmentary matter. 



The microscopical examinations by Dr. Landois and others leave no doubt as to the 

 cause of the white color of the hair in cases of sudden blanching ; and the instances we 

 have just quoted show that the fact of the occurrence of this phenomenon can no longer 

 be called in question. All are agreed that there is no diminution in the pigment, but that 

 the greater part of the medulla becomes filled with air, small globules being also found 

 in the cortical substance. The hair in these cases presents a marked contrast with hair 

 that has become gray gradually from old age, when there is always a loss of pigment in 

 the cortex and medulla. How the air finds its way into the hair in sudden blanching, it 

 is difficult to imagine ; and the views that have been expressed on this subject by different 

 authors are entirely theoretical. 



The fact that the hair may become white or gray in the course of a few hours renders 

 it probable that many of the cases reported upon unscientific authority actually occurred ; 

 and these have all been supposed to be connected with intense grief or terror. The terror 

 was very marked in the case reported by Dr. Landois. In the great majority of recorded 

 observations, the sudden blanching of the hair has been apparently connected with intense 

 mental emotion; but this is all that can be said on the subject of causation, and the 

 mechanism of the change is not understood. 



Uses of the Hairs. The hairs serve an important purpose in the protection of the 

 general surface and in guarding certain of the orifices of the body. The hair upon the 

 head and the face protects from cold and shields the head from the rays of the sun during 

 exposure in hot climates. Although the amount of hair upon the general surface is small, 

 as it is a very imperfect conductor of caloric, it serves in a degree to maintain the heat 

 of the body. It also moderates the friction upon the surface. The eyebrows prevent the 

 perspiration from running from the forehead upon the lids; the eyelashes protect the 

 surface of the conjunctiva from dust and other foreign matters ; the mustache protects 

 the lungs from dust, a function very important in persons exposed to dust in long journeys 

 or in their daily work ; and the short, stiff hairs at the openings of the ears and nose pro- 



