of the human bcdy. He was the first to insist on analogies of structure between organs throughout the animal kingdom, and to make extensive practical use of the idea, that discoveries on simpler animals can be utilized in interpreting the similar structures in the higher ones.
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 observations of Leeuwenhoek, nevertheless the work of Leeuwenhoek 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 pigmentary 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 observations on glands were 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 the spleen. He was also the first to indicate the presence of papillæ on the tongue. This 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 marvels of organic architecture were being made known in the human body and the higher animals, but mo insect—hardly, indeed, any animal—had then been carefully described, and all the methods of work had to be discovered.' The delicacy, beauty and intricacy of the organic systems in this group of animals were well calculated to arouse wonder and admiration. He worked with such enthusiasm in this new territory as to throw himself into a fever and to set up an inflammation in the eyes. "Nevertheless," says Malpighi, "in performing these researches so many marvels of nature were spread before my eyes that I experienced an internal pleasure that my pen could not describe." In the words of Miall:
