Page:Popular Science Monthly Volume 58.djvu/575

Rh  transformation were observed, to give any adequate credit to the writer of this masterly study. Treading A new path, he walks steadily forward, trusting to his own sure eves and cautious judgment. The descriptions are brief and simple, the figures clear, inn not rich in detail. There would now be much to add to Malpighi's account, but hardly anything to correct. The only positive mistakes which meet the eye relate to the number of spiracles and nervous ganglia—mistakes promptly corrected by Swammerdam."

He showed that the method of breathing was neither by lungs nor gills, but through a system of air-tubes, communicating with the exterior through button-hole shaped openings, and. internally, by an infinitude

of branches reaching to the minutest parts of the body. Malpighi showed an instinct for comparison; instead of confining his researches to the species in hand, he extended his observations to other insects, and he gives sketches of the breathing tubes, held open by their spiral thread, taken from several species.

The nervous system he found to be a central white cord with swellings in each ring of the body, from which nerves are given off to all organs and tissue. The cord which is, of course, the central nervous system, he found located mainly on the ventral surface of the body, but extending by a sort of collar of nervous matter around the œsophagus and, on the dorsal surface, appearing as a more complex mass, or brain,