606 



SCIENCE 



[Vol. LV, No. 1432 



Gradually, all the toe bones except one— the 

 middle toe — have been lost. But the second 

 and fourth digits, though they do not show 

 externally, are represented by two rudimentary 

 bones, the two "splint bones." The horse of 

 to-day walks literally on tip toe, for the hoof 

 is the toe- or finger-nail. 



III. The internal organs of the body have 

 the same story to tell of likeness or identity. 

 Let us first look at the heart. You all know 

 there is a right side of the heart which sends 

 the blood through the lungs to be oxygenated, 

 and a left side, which sends the blood to all the 

 rest of the body. Each of these sides has two 

 cavities — ^the auricle to collect the blood, the 

 other, the ventricle, with strong, muscular 

 walls, to drive the blood on its long journey. 

 These four cavities are all united into one 

 heart, with an imiJortant groove on the surface, 

 m'arking a partition between the two auricles 

 above and the two centricles below. 



A steady, rhythmical action of the four cavi- 

 ties is essential for the proper propulsion of 

 the blood, and, therefore, for health and life. 

 The four cavities act, not all at once, but in 

 succession, like the feet of a walking horse — 

 1, 2, 3, 4; 1, 2, 3, 4, each foot having its own 

 number. Until 1892 we did not know exactly 

 what regulated this orderly sequence. In that 

 year, the younger Professor His discovered 

 that in the groove between the auricles and the 

 ventricles there was a small bundle of muscular 

 fibers which existed as one bundle until it 

 reached a certain point. There it divided into 

 two smaller bundles, one going to the muscles 

 of the right side of the heart, and the other to 

 those of the left side. 



But the great importance of this "bundle of 

 His" was not fully appreciated until twelve 

 years later (1904). If, under an anesthetic, 

 an animal's chest is opened, the heart laid bare, 

 and this "bundle of His" is injured, the rhythm 

 of the heart is at once disturbed. Instead of 

 1, 2, 3, 4, the order in which tlie hoofs struck 

 the ground might be 1, 4, 2, 3, or 1, 3, 2, 4, etc. 

 This fluttering of the heart threatens life. If 

 the bundle is destroyed, death quickly follows. 



In man, such physiological experiments, of 

 course, are forbidden, but occasionally disease 

 maims or destrovs this bundle of His in the 



human heart itself. A small tumor named a 

 gmnma, in a few eases, has formed directly in 

 or near the bundle of His, and in some cases 

 has destroyed it. This has deranged the action 

 of the heart of -the human patient, just as the 

 physiologist did in the experimental animal. 

 Severe flutterings of the human heart, with 

 difficulty of breathing, a pulse slowed down 

 from 72 to 20, 10 or even 5 in the minute were 

 observed. Not seldom sudden death occurred. 

 The post-mortem in these cases disclosed the 

 tumor, or other cause, which had injured or 

 destroyed this bundle of His, and was the imme- 

 diate cause of death. 



Now, this bundle of His is found in all ver- 

 tebrates, in man and other mammals, in liirds, 

 and even in frogs and fishes. Does not this 

 show a solidarity of the entire animal kingdom? 

 Do not so many such exact parallels between 

 the human and the animal body strongly sug- 

 gest a close inter-relation of the two? 



Even plants convey the same message. I 

 have seen Professor Bose, of Calcutta, put. 

 plants to sleep with ether and chloroform. If 

 enough is given, they are killed just as a man 

 is killed. If only a moderate dose is given, the 

 plant passes into a state of greatly lessened 

 activity, which may be well called sleep. When 

 the anesthetic is withdrawn, it gradually wakens, 

 and returns to its normal activity, just as a 

 man does. 



One can even descend still further down in 

 the scale to the bacteria, that is, germs visible 

 only by the microscope. As Welch, of the 

 Johns Hopkins, points out, "The gentle killing 

 of certain bacteria by chloroform enables us to^ 

 detect in their bodies toxic [poisonous] sub- 

 stances which are destroyed by more violent 

 modes of death." 



IV. The Liver and the Ductless Glands. 

 Everybody knows that the liver secretes bile, 

 or gall. The bile, which is necessary for proper 

 digestion, is discharged into the intestine 

 through a tube called the bile duct. The gall 

 bladder is simply a reservoir for extra bile, 

 and a sturdy means of support for us surgeons, 

 especially in the late hard times^ — by reason of 

 the dangerous gall stones which form in it and 

 require removal by a surgical operation. 



Now, in 1848, Claude Bernard, of Paris, one 



