786 THE POPULAR SCIENCE MONTHLY. 



knowledge of the functions of the brain. Its career must some- 

 what resemble that of the art of medicine. There were great 

 physicians before Harvey found a starting-point for scientific 

 physiology ; yet the debt of practical medicine to physiology is 

 now well-nigh incalculable. So it will be with the art of teach- 

 ing: noble work has been done for its advancement in entire 

 ignorance of the organ whose best development it seeks ; but now, 

 since there is already a large and constantly increasing fund of 

 knowledge concerning the working of the brain, teachers who 

 are not bound to the traditions of the past, but are looking 

 eagerly for every means of improving their art, will assuredly 

 not fail to take advantage of the new knowledge. 



The result must be an enormous gain for the children of the 

 future.* 



An influence of a total solar eclipse on air pressure has been deduced by Herr 

 Steen from the comparison of the records of fourteen Norwegian ships between 

 Panama and Madagascar, during the eclipse of August 29, 1885, four of the ships 

 having been within the zone of totality and four others very near it. Two maxi- 

 ma of pressure, separated by a minimum, were revealed. The double wave is 

 explained by Herr Steen by assuming that during a solar eclipse day is changed 

 to night for a short time, and the transition is much like the ordinary change 

 from day to night in the tropics, where the twilight is short. There the curve 

 of air pressure has regularly a maximum about 10 p. m., some time after sun- 

 set, and a minimum about 4 a. m., shortly before sunrise; while a second maxi- 

 mum appears about 4 a. m. A total solar eclipse would naturally act in a simi- 

 lar way. 



* References. Any reader interested in the foregoing argument would do well to 

 verify the statements of fact on which it is based by reference to some of the following 

 well-known authorities : 



For a very clear, popular account of the functions of the brain, see Prof. M. A. Starr's 

 article, The Old and the New Phrenology, Popular Science Monthly, October, 1889. 



For a more complete account, consult the same author's Familiar Forms of Xervous 

 Disease ; Gowers's Diseases of the Nervous System, pp. 454-465, American edition ; and the 

 text-books of physiology by Michael Foster and by Landois and Stirling. 



For defects in the use of language, besides the above, see Th. Ribot, Diseases of 

 Memory, chap, iii ; Moebius, Allgemeine Diagnostik der Nervenkrankheiten ; Ross, Dis- 

 eases of the Nervous System, chap, xviii ; H. C. Wood, Nervous Diseases and their Diag- 

 nosis, chap, ix ; Gowers, loc. cit., pp. 540-555 ; also Starr, The Pathology of Sensory 

 Aphasia, Brain, July, 1889, and Apraxia and Aphasia, Medical Record, October 27, 1888. 



For a discussion of word-blindness and mind-blindness, illustrated by cases of great 

 interest, see Charcot, Lecnns sur les Maladies du Systeme Nerveux, tome iii, pp. 154189. 



For a discussion of the working of the brain in reading, with references to previous re- 

 searches, see Ein Beitrag zur Lehre von den Lesestoerungen, Weissenberg, Archiv f. Psy- 

 chiatric, xxii, 2. 



The most philosophical and elaborate work on the disturbances of speech is that con- 

 tributed by Kussmaul to Ziemmsen's Cyclopaedia, vol. xiv. 



In consulting any author on this subject the date of writing must, of course, be consid- 

 ered, as every year adds materially to the common store of available facts. 



