74 THE POPULAR SCIENCE MONTHLY. 



expense of the patient, and then die out again. Indeed, it seems to 

 be thoroughly established that many diseases are due to the excessive 

 multiplication of microscopic organisms, and we are not without hope 

 that means will be discovered by which, without injury to the patient, 

 these terrible though minute enemies may be destroyed, and the dis- 

 ease thus stayed. The interesting researches of Burdon-Sanderson, 

 Greenfield, Koch, Pasteur, Toussaint, and others, seem to justify the 

 hope that we may be able to modify these and other germs, and then 

 by appropriate inoculation to protect ourselves against fever and other 

 acute diseases. 



The history of anaesthetics is a most remarkable illustration of how 

 long we may be on the very verge of a most important discovery. 

 Ether, which, as we all know, produces perfect insensibility to pain, was 

 discovered as long ago as 1540. The anaesthetic property of nitrous 

 oxide, now so extensively used, was observed in 1800 by Sir H. Davy, 

 who actually experimented on himself, and had one of his teeth pain- 

 lessly extracted when under its influence. He even suggests that, 

 " as nitrous oxide gas seems capable of destroying pain, it could prob- 

 ably be used with advantage in surgical operations." Nay, this prop- 

 erty of nitrous oxide was habitually explained and illustrated in the 

 chemical lectures given in hospitals, and yet for fifty years the gas was 

 never used in actual operations. 



Few branches of science have made more rapid progress in the last 

 half-century than that which deals with the ancient condition of man. 

 When our Association was founded, it was generally considered that 

 the human race suddenly appeared on the scene, about six thousand 

 years ago, after the disappearance of the extinct mammalia, and when 

 Europe, both as regards physical conditions and the other animals by 

 which it was inhabited, was pretty much in the same condition as in 

 the period covered by Greek and Roman history. Since then the per- 

 severing researches of Layard, Rawlinson, Botta, and others have 

 made known to us, not only the statues and palaces of the ancient 

 Assyrian monarchs, but even their libraries ; the cuneiform characters 

 have been deciphered, and we can not only see, but read in the British 

 Museum, the actual contemporary records, on burned-clay cylinders, of 

 the events recorded in the historical books of the Old Testament and 

 in the pages of Herodotus. The researches in Egypt also seem to have 

 satisfactorily established the fact that the pyramids themselves are at 

 least six thousand years old, while it is obvious that the Assyrian and 

 Egyptian monarchies can not suddenly have attained to the wealth 

 and power, the state of social organization, and progress in the arts, 

 of which we have before us, preserved by the sand of the desert from 

 the ravages of man, such wonderful proofs. 



In Europe, the writings of the earliest historians and poets indi- 

 cated that, before iron came into general use, there was a time when 

 bronze was the ordinary material of weapons, axes, and other cutting 



