POP ULAR MIS CELL ANY 



281 



rally associate with those of our own time. 

 The law of progress has been dominant 

 among plants and animals, and not less 

 upon the surface of the planet which they 

 inhabit. It is the province of the biologist 

 to trace the one series of changes, of the 

 geologist to investigate the other. The 

 geographer gathers from both the data 

 which enable him to connect the present 

 aspects of nature with those out of which 

 they have arisen. 



Storms and Neuralgia. At vhe April 

 meeting of the National Academy of Sci- 

 ences, Dr. S. Weir Mitchell read a paper on 

 " The Relation of Neuralgic Pain to Storms 

 and the Earth's Magnetism." The interest- 

 ing observations here recorded were made 

 by Dr. Mitchell in conjunction with Captain 

 Catlin, of the United States Army, who lost 

 a leg during the war, and who, since that 

 time, has suffered from traumatic neuralgia, 

 sometimes in the heel, but more frequently 

 in the toes, of the lost foot. The hourly 

 observations cover a period of five years. 

 For the first quarters of these five years 

 there were 2,471 hours of pain ; for the sec- 

 ond quarters, 2,102 hours; for the third 

 quarters, 2,056 hours; and for the last quar- 

 ters, 2,221 hours. The greatest number of 

 hours of pain is in January, February, and 

 March ; and the least in the third quarters, 

 July, August, and September. During these 

 five years, while the sun was south of the 

 equator, there were 4,692 hours of pain, 

 against 4,158 hours while it was north of 

 the equator; and the greatest amount of 

 pain was in the quarters beginning with the 

 winter solstice, and the least was in those 

 beginning with the summer solstice. The 

 avei'age duration of the attacks for the first 

 quarters was 22 hours, and for the third 

 quarters only 17'9 hours. By taking the 

 four years ending January 1, 18*79, it is 

 found that, of the 537 storms charted by 

 the Signal Bureau, 298 belong to the two 

 winter quarters, against 2S9 for the summer 

 quarters. Hence we have the ratio of the 

 number of storms of the winter quarters 

 and summer quarters corresponding to the 

 ratio of the amounts of neuralgia for these 

 respective periods, and the ratio of average 

 duration of each attack for the same time 

 corresponds closely with the ratio of the 



respective total amounts of neuralgia for 

 the same periods. The average distance of 

 the storm-center at the beginning of the 

 neuralgia attacks was 680 miles. Storms 

 coming from the Pacific coast are felt far- 

 thest off, while storms along the Atlantic coast 

 are associated with milder forms of neural- 

 gia, and are not felt until the storm-center 

 is nearer. Rain is not essential in the pro- 

 duction of neuralgia. It was found that the 

 severest neuralgic attacks of the year were 

 those accompanying the first snows of No- 

 vember and December. Every storm, as it 

 sweeps across the continent, consists of a 

 vast rain area, at the center of which is a 

 moving space of greatest barometric de- 

 pression, known as the storm-center, along 

 which the storm moves like a bead on a 

 thread. The rain usually precedes this by 

 550 to 600 miles ; but before and around 

 the rain lies a belt which may be called the 

 neuralgic margin of the storm, and which 

 precedes the rain about 150 miles. This 

 fact is very deceptive, because the sufferer 

 may be on the far edge of the storm-basin 

 of barometric depression, and see nothing 

 of the rain, yet have paiu due to the storm. 



Physiological Action of Aconite. From 



certain experimental inquiries into the phys- 

 iological action of aconite and its alkaloid, 

 aconitia. Dr. G. H. Mackenzie concludes that 

 these drugs act primarily on the respiration 

 by their influence on the respiratory center 

 and peripheral sensory branches of the va- 

 gus nerve. They have no direct action on 

 the heart, and only affect that organ sec- 

 ondarily through the medium of the lungs. 

 Their action on the nervous system consists 

 in firstly irritating and secondly paralyzing 

 the peripheral sensory nerves and posterior 

 roots of the spinal nerves. They have no 

 direct action on the brain or the vaso-motor 

 nerves. They increase the irritability of the 

 peripheral motor nerves, and of the motor 

 columns of the cord. They do not induce 

 muscular paralysis, but, on the contrary, in- 

 crease the irritability of voluntary muscle. 

 They induce convulsions mainly through 

 their augmenting the irritability of the an- 

 terior column of the cord, the motor nerves, 

 and muscles. They firstly increase and sec- 

 ondly diminish temperature. Death ensues 

 from asphyxia and respiratory collapse. 



