CH. xvii. FIRST USE OF THE MICROSCOPE. 135 



to the study of the structure of living beings we owe to 

 Malpighi. 



Marcello Malpighi was born at Crevalcuore, near Bologna, 

 in the year 1628 ; he became Professor of Medicine at the 

 University of Bologna in 1656, and was early distinguished 

 for his discoveries in Anatomy, made chiefly by the use of 

 the microscope. It is not possible without a knowledge 

 of anatomy, to understand thoroughly the structures which 

 he described, but we may be able to form a general idea 

 of the work he did. 



One of his first experiments was the examination of the 

 general circulation of the blood in the stomach of a frog, 

 and he succeeded in demonstrating the fact that the arteries* 

 are connected with the veins by means of minute tubes 

 called capillaries, thus proving beyond doubt the truth 01 

 Harvey's doctrine. His next work was to study the passage 

 of the blood through the lungs (see p. 1 1 1), and to describe 

 the air-cells from which the blood derives its oxygen. If 

 you can get anyone to show you properly under the micro- 

 scope a section of a frog's lung, you will see a number of 

 round spaces bordered by a delicate partition; these are 

 sections of air-cells, and round them you will see a network 

 of minute tubes. Through these tubes or capillaries the 

 blood flows in a living creature, and takes up oxygen from 

 the air through the coverings or membranes of the air-cells 

 and capillaries, giving back carbonic acid in exchange to 

 be breathed out into the atmosphere. Malpighi was the 

 first to point out these air-cells, and to describe the way in 

 which the blood passes over them. After this he turned his 

 attention to the tongue, and published in 1665 a careful de- 

 scription of all its nerves, vessels, and coverings. He also 

 pointed out that the outside layer of the skin or epidermis 

 of the negro is as white as yours or mine, and that the 



