Chemistry and Physics. 435 



adjacent curves. " Two curves must be widely different in shape 

 and position, before the colour-perceiving center can detect the 

 difference. A curve has an infinite number of points on it. 

 The colour-perceiving center is so badly developed that, as far as 

 it is concerned, the curve is sufficiently specified by three points 

 on it, provided that these points are distributed over the spec- 

 trum. We can therefore represent our energy curve by three 

 points." — Proc. Roy. Hoc, vol. xcii (A), p. 424, July 1916. 



h. s. u. 

 6. On the Auditory Sense. — An interesting and doubtless 

 important contribution to our knowledge of the sense of hearing 

 has recently been made by M. Maeage. The paper in question 

 is the result of a careful scientific study of the various phases of 

 deafness arising from certain kinds of injuries suffered by the 

 French soldiers in the present war. The author divides the 

 causes of the special sorts of deafness, with which he is pri- 

 marily concerned, into two classes : (a) a fragment of an ordinary 

 shell or a rifle ball strikes the skull at a point more or less remote 

 from the ear in such a manner as not to produce any direct lesion 

 of the brain. The shock always gives rise to general headaches, 

 buzzing, partial loss of memory, lowering of audition, and slight 

 trembling of the members, (b) A shell of the largest caliber 

 explodes in the immediate vicinity (from 1 to 4 meters) of a 

 soldier. No apparent wound exists, but the symptoms just speci- 

 fied are met with in an exaggerated degree. Loss of conscious- 

 ness lasts from a few hours to six days ; very violent pains in the 

 frontal region persist for several months ; very pronounced buzz- 

 ing which gradually disappears ; complete loss of memory ; abso- 

 lute or nearly complete deafness (sometimes the patient hears but 

 does not understand) ; violent trembling, especially of the upper 

 portions of the body ; and sometimes total deaf-muteness. 



The apparatus used is a motor-driven siren designed to produce 

 the sounds on, o, a, e, and i. The intensity of the vowel sounds 

 emitted can be estimated from the indications of a pressure gauge. 

 From a statistical study of numerous cases Marage has established 

 the fact that there are four and only four curves corresponding 

 to the various types of partial deafness. Two curves are asso- 

 ciated with injuries to the middle ear, and two pertain to lesions 

 of the internal ear and to the auditory centers. These graphs 

 are plotted with the vowels equally spaced as abscissas and with 

 the corresponding least intensities audible as ordinates. The 

 manner of examining a patient seems quite simple since it con- 

 sists in sounding one vowel at a time while increasing the inten- 

 sity until the subject indicates that he just begins to hear the note. 

 The manometer is, of course, hidden from the view of the person 

 under examination. The next day, or even a few minutes later, 

 the process is repeated. An honest patient alwaj^s reproduces 

 the first set of data, whereas a simulator of partial deafness can 

 never remember the intensities of all the five notes specified by 

 him in the first test as inferior limits of hearino-. A case of 



