SCIENTIFIC PROGRESS. 493 



parative psychology, analogous to comparative anatomy, which latter 

 has been in an advanced stage for a long time. Finally, in the 

 psychological domain we owe to modern times the knowledge of the 

 strange phenomena of double consciousness and of hypnotism with 

 the phenomena of suggestion, the study of which is calculated to 

 throw on the mental being more light than could the most volumi- 

 nous works on psychology of former times, which were the result of 

 self-observation and self-deification. Unfortunately, these phenom- 

 ena have given food to the inextirpable belief in miracles, and 

 furnished new support for unfounded spiritualistic and spiritistic 

 chimeras of every kind, such as thought-reading, telepathy, magnetic 

 rapport, the belief in ghosts, spooks, etc. 



Medicine. If we finally mention medicine or therapeutics as 

 a branch of physical science we have here also to record a series 

 of the most important advances in the course of the century. At 

 the head stands the method of auscultation or of listening by means 

 of an ear trumpet to the sounds in the chest in order to discover dis- 

 ease in the lungs and the heart. This method was invented by the 

 French physician Laennec in 1819, soon after the method of per- 

 cussion had been improved by Piorry, while the foundation of 

 pathological anatomy through Professor Rokitansky, and of patho- 

 logical histology by Professor Yirchow, which soon after followed, 

 advanced medicine to a real science. Another invention, highly 

 important in practice subcutaneous injection was made by A. 

 Wood in 1850. More recent than all this is the very important dis- 

 covery of the infectious micro-organisms or bacteria as the causes 

 of disease. This discovery, which led to the application of disinfec- 

 tion, in common with the introduction of chloroform and cocaine as 

 anaesthetics, on the one hand, cleared the way for the acknowledged 

 wonderful progress made in surgery, and, on the other hand, materi- 

 ally facilitated the combating of diseases caused by those organisms 

 by prophylactic measures. 



We must also allude to the invention of a great number of new 

 remedies obtained by means of chemistry, as well as of new methods 

 of curing ailments (e. g., massage). We must mention, too, the gen- 

 eral introduction of vaccination, which has proved one of the great- 

 est blessings to mankind. Whether the injection of fluids as an im- 

 munity against certain diseases (e. g., diphtheria), tried according to 

 the same method, will fulfill the hope entertained is a question the 

 solution of which must be awaited after the unfortunate failure of a 

 similar procedure employed in tuberculosis. It seems, however, as 

 though this so-called " serum therapeutics " in its further develop- 

 ment might accomplish great results in the field of infectious dis- 

 eases. The ascertaining and location of internal diseases (particu- 



