Sept. 5, 1884.] 



♦ KNOWLEDGE ♦ 



201 



then is an eclipse of the sun to us during our day, and an 

 eclipse of the earth to the moon during her night. When 

 it is full moon the earth is between her and the sun, and 

 all the dark half of the earth is turned towards all the 

 light half of the moon ; the shadow then of the earth c£ista 

 itself towards the moon, and if it falls on the moon, it 

 obscures that light half which we see, which has then day, 

 and hinders the sun from shining on it. Here then is an 

 eclipse of the moou to us during our night,* and an eclipse 

 of the sun to the moon during her day ; but the reason 

 that we have not eclipses every time that the moon is 

 between the sun and the earth, or the earth between the 

 sun and the moon, is because these three bodies are not 

 exactly placed in a right line ; and by consequence that 

 which should make the eclipse, casts its shadow a little 

 beside that which should be obscured." 



" I am surprized,' said the Marchioness, " that there 

 should be so little mystery in eclipses, and that the whole 

 world .should not know the cause of 'em." 



" They never will," said I, " as some jieople go about it 

 In the East Indies, when the sun and the moon are in 

 eclipse, they believe a certain devil who has black claws, 

 is seizing on those planets with his talons ; and during that 

 time the rivers are covered with the heads of Indians, who 

 are up to the neck in water, because they esteem it a very 

 devout posture, to implore the sun and the moon to defend 

 them against the devil. In America, they are persuaded 

 that the sun and the moon, when eclipsed, are angry, and 

 what is it they will not do to be reconciled with them 1 

 The Greeks, who were so refined, did they not believe the 

 moon was enchanted, and that the magicians forced her to 

 descend from heaven, and shed a dangerous juice on the 

 plants ■? Nay, what a panic were we in, not many years 

 ago, at an eclipse of the sun 1 How many people hid 

 themselves in their cellars ; and all the philosophers could 

 not persuade them to come out till the eclipse was overl" 



"Methinks," said she. "'tis scandalous for men to be 

 such cowards ; there ought to Ije a general law made to 

 prohibit the discoursing of eclipses, that we might not call 

 to mind the follies that have been said and done upon that 

 subject." 



" Your law then," said I, " must abolish even the 

 memory of all things, and forbid us to speak at all, for I 

 know nothing in the world which is not a monument of 

 the folly of man." 



(To be continued.") 



MUSCULAR CONTRACTION AFTER 

 DBATH.t 



DR. BROWN-SfiQUARD maintains that lixed and 

 rigid positions after death, speedily ensuing, are due 

 to the last vital act, which has induced a " tonic contrac- 

 tion," and that causes of death which produce sudden 

 dissolutions without pain or excitement may be the means 

 of such a contraction. Assuming this to be true, still the 

 modus operandi by which a vital act can leave such a " tonic 

 contraction " after all vital power has ceased is not suggested 

 by him, and we need one step further in the way of en- 

 lightenment. Let us see if we cannot take that step now. 

 In accordance with the observations of Du Bois Reymond, 

 it has been pretty generally accepted that the normal state 

 of even quiescent living muscle is one of electrical tension, 

 and that during muscular contraction the tension diminishes 



Or rather, daring the night of the parts of the earth turned 

 moonwards. — E. P. 



t From the Scientific American. 



in such a way that as the wave of contraction moves along 

 the muscle it is preceded by a wave of negative variation. 

 This variation is slight for a single contraction, but in those 

 of great rapidity it may become so great as to completely 

 neutralise the galvanometric deflection due to the normal 

 current of the quiescent muscle. 



These views have been attacked and sharply criticised, 

 notably by Hermann in 1807, and as lately as 1877 Engel- 

 mann has come to Hermann's aid in Pfluger's "Archiv." 

 They maintain that normal muscle-currents do not exist ; 

 and that those observed by Du Bois Reymond were due to 

 the unnatural conditions of the muscles examined by him. 

 He, however, has replied to their criticisms with great 

 ability, and his views are now, as already stated, very gene- 

 rally adopted by physiologists. A consideration of these 

 views may perhaps hel[i us to a clearer idea of the position 

 of the headless soldier of Sedan, as shown in Brown- 

 Sequard's figure. 



The conditions required, in order that a limb or the 

 entire body should be in a state of rigidity, are simply that 

 the antagonistic muscles, the flexors and extensors, for 

 instance, should be braced at the same moment to full 

 activity, and the rigidity continues so long as the mutual 

 action remains. If this action is not local, but general, 

 such a figure will continue without motion indefinitely, 

 excepting that gravitation may cause it to fall to the 

 ground, if unsupported. But even such a fall would not 

 aflTect the limbs : they would necessarily retain their 

 position. 



Now Du Bois Reymond has shown us that tonic contrac- 

 tion is the normal state of muscle fibre, and that relaxation 

 is due to an accession of vital activity through the agency 

 of nerve force. We know well that commonly when life 

 ceases muscular contractility ceases with it. And we can 

 readily see that when death comes as the result of disease 

 or exhaustion, and is attended with suflfering, the pertur- 

 bation of nerve force and of muscle currents must be so 

 great that such a result wUl surely follow. And as these 

 include death in almost every form in which we ever 

 witness it, we have naturally come to understand that mus- 

 cular relaxation is its normal attendant and its immediate 

 result "He bowed his head" is the fearfully expressive 

 term employed when death came on Calvary. 



But in the very few instances where death occurs suddenly 

 and without suffering, it seems possible that the instanta- 

 neous cessation of the nerve force may leave every muscle 

 fibre in its normal condition. If that could be, universal 

 rigidity would instantaneously ensue, and the last position 

 assumed in life Wduld be retained in death. Now, we 

 know that the one cause of all causes which can bring a 

 death into which the element of time does not enter is a 

 wound which obliterates the base of the brain as well as the 

 commencement of the spinal cord. That there is an interval 

 between the cause and efl!ect is doubtless theoretically true, 

 but practically the interval has no existence, for it is infini- 

 tesimal. Such a stroke must necessarily be painless, for 

 life (including of course sensation) is abolished at its occur- 

 rence. The two chief eases cited by Brown-Sequard are 

 cases precisely in point. 



The cannon-ball at Sedan left nothing remaining above 

 the lower jaw. The brain of the soldier at Goldsborough 

 had been swept by a bullet from a Springfield rifle, that 

 struck him in the right temple, while his head was turned 

 toward his right shoulder, and beyond question inclined 

 downward, for his leg had that instant crossed the saddle, 

 and the stock of his own rifle was still on the ground. 

 Following Du Bois Reymond, it is diificult to see how 

 instantaneous rigidity should not ensue in each of these 

 cases ; it did ensue, whether our explanation be correct 



