Russia's Contribution to Science. 231 



25 years ago on the suljject of "What is Thought?" Unassum- 

 ing and quiet, he spoke in the immense assembly hall of the 

 Moscow nobility without raising his voice which nevertheless 

 was heard by everybody in the audience. 



Prince Ivan Romanovitch Tarkhan Mouravov, better known 

 as Tarkhanoff, a Georgian by nationality, born in 1846, was for 

 many years professor of physiology at the Medical Academy of 

 St. Petersburg. His works embrace the physiology of thermic 

 reflexes, the innervation of the spleen, the application of the tele- 

 phone to the study of animal electricity, the physiology of the 

 normal sleep in animals, the automatic movements of decapitated 

 animals, the influence of music on animals and man, etc. 



The physiologist best known in foreign countries and one of 

 the most remarkable experimenters of the world is Ivan Petro- 

 vitch Pavlov, born in 1849 ^"^ professor of physiology at the 

 ^ledical Academy of St. Petersburg since 1890. His investiga- 

 tions extending over many years and contained in numerous 

 articles ma}' be divided into three groups : work relating to the 

 innervation of the heart, work in connection with the so-called 

 Eck fistula, and work on the secreting activity of the stomach. In 

 the first series of papers, Pavlov has shown that besides centers 

 accelerating and retarding the heartbeat, the heart possesses also 

 centers augmenting and depressing the strength of the heart- 

 beat. In the second series of experiments Pavlov used the opera- 

 tion suggested by his teacher Eck and consisting in an artificial 

 connection of the portal vein with the inferior caval vein. 

 Through this connection the blood flowing from the digestive 

 organs was diverted from the liver and the function of the latter 

 organ can be studied independently. It was thus that Pavlov was 

 enabled to show how the liver acts as an organ absorbing from 

 the blood harmful substances and purifying it. 



But the most celebrated of his investigations are those based on 

 oesophagotomy, i. e., on an operation consisting in the severing of 

 the oesophagus and the production of an artificial fistula, allow- 

 ing a direct observation of the contents of the stomach under 

 various conditions. This operation is too well known to require 

 an explanation or detailed description here. The results of these 

 investigations, which have been translated into many languages, 

 may be briefly summarized as follows : the secretion of saliva is 

 caused by refl.exes through smell, sight, etc., before food is taken 



