PROGRESS OF MEDICINE IN THE NINETEENTH CENTURY. 641 



of the remark that a certain patented form of electric light was sur- 

 rounded by a cloud of nonluminous verbosity. For example, the com- 

 mittee of the Medical Society of the State of New York reported that 

 yellow fever may be produced in any country by pestilential effluvia; 

 and AYebster concluded that typhus and nervous fevers were due to 

 a "-conversion of the perspirable fluids of the body into septic mat- 

 ter "—all of which means that they knew nothing about it. Even now 

 we do not know the cause of yellow fever, or the precise mode of its 

 spread; but we are sufficiently certain that it is due to a specitic micro- 

 organism to be confident that its spread can ])e checked by isolation 

 and disinfection properly applied— and Memphis and New Orleans are 

 witnesses of the truth of this. 



In the year 1800 the majority of persons over 20 years old were 

 more or less pitted by smallpox, being the survivors of a much greater 

 number who had suffered from this disease. Dr. Miller in New York 

 had just received from England a thread which had been steeped in 

 the newly discovered vaccine matter, and was about to begin vaccina- 

 tion in that city. To-da}^ there are many physicians who have never 

 seen a case of smallpox, and a face pitted with the marks of this 

 disease is rarely seen. During the century there have appeared in 

 civilized countries two strange and unfamiliar forms of epidemic 

 disease, namely, Asiatic cholera and the plague, the first coming from 

 the valley of the Ganges, the second from the valley of the Euphrates, 

 and each having a long history. A really new disease was the out- 

 break in Paris in 1892 of a specific contagious disease transmitted 

 from sick parrots, and known as psittacosis. This little epidemic 

 affected 49 persons and caused 16 deaths. Typhus fever has almost dis- 

 appeared, while some diseases have increased in relative frequency', in 

 part at least because of medical progress. The children who would 

 have died of smallpox in the eighteenth century now live to be affected 

 with diphtheria or scarlet fever, and the increase in the lumiber of 

 deaths reported as due to cancer is partly due to the fact that a greater 

 proportion of people live to the age most subject to this disease. 



A large part of modern progress in medicine is due to improved 

 methods of diagnosis and to the use of instruments of precision for 

 recording the results of examinations. The use of the clinical ther- 

 mometer has effected a revolution in medical practice. Our knowl- 

 edge of diseases of the heart and lungs has been greatly expanded 

 during the century by auscultation and percussion, and especially by 

 the use of the stethoscope. The test tube and the microscope warn us 

 of kidney troubles, which formerly would not have been suspected, 

 and the mysterious Roentgen rays are called in to aid the surgeon in 

 locating foreign bodies and in determining the precise nature of cer- 

 tain injuries of the bones. Bacteriological examination has become a 



