INTRODUCTION OF THE MICROSCOPE 63 



It is very interesting to note that in connection with this 

 work he actually observed the passage of blood through the 

 capillaries of the transparent lungs of the frog, and also in 

 the mesentery. Although this antedates the similar obser- 

 vations of Leeuwenhoek (1669), nevertheless the work of 

 Lceuwenhoek was much more complete, and he is usually 

 recognized in physiology as the discoverer of the capillary 

 connection between arteries and veins. At this same period 

 Malpighi also observed the blood corpuscles. 



Soon after he demonstrated the mucous layer, or pigment- 

 ary layer of the skin, intermediate between the true and the 

 scarf skin. He had separated this layer by boiling and 

 maceration, and described it as a reticulated membrane. 

 Even its existence was for a long time controverted, but it 

 remains in modern anatomy under the title of the Malpighian 

 layer. 



His observation of glands was extensive, and while it must 

 be confessed that many of his conclusions in reference to 

 glandular structure were erroneous, he left his name connected 

 with the Malpighian corpuscles of the kidney and of the 

 spleen. He was also the first to indicate the nature of the 

 papillae on the tongue. The foregoing is a respectable list of 

 discoveries, but much more stands to his credit. Those which 

 follow have a bearing on comparative anatomy, zoology, and 

 botany. / 



Monograph on the Structure and Metamorphosis of the 

 Silkworm. — Malpighi's work on the structure of the silkworm 

 takes rank among the most famous monographs on the 

 anatomy of a single animal. Much skill was required to 

 give to the world this picture of minute structure. The mar- 

 vels of organic architecture were being made known in the 

 human body and the higher animals, but "no insect — hardly, 

 Indeed, any animal — had then been carefully described, and 

 all the methods of the work had to be discovered." He 



