64 BIOLOGY AND ITS MAKERS 
labored 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 re- 
searches so many marvels of nature were spread before my 
eyes that I experienced an internal pleasure that my pen 
could not describe.”’ 
He showed that the method of breathing was neither by 
lungs nor by gills, but through a system of air-tubes, com- 
municating with the exterior through buttonhole-shaped 
openings, and, internally, by an infinitude of branches reach- 
ing 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 has given 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 cach ring of the bedy, from which nerves 
are given off to all organs and tissues. 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 cesophagus, and on 
the dorsal surface appearing as a more complex mass, or 
brain, from which nerves are given off to the eyes and other 
sense organs of the head. As illustrations from this mono- 
graph we have, in Fig. 14, reduced sketches of the drawings 
of the nervous system and the food canal in the adult silk- 
worm. ‘The sketch at the right hand illustrates the central 
nerve cord with its ganglionic enlargement in cach segment, 
the segments being indicated by the rows of spiracles at the 
sides. The original drawing is on a much larger scale, 
and reducing it takes away some of its coarseness. All 
of his drawings lack the finish and detail of Swammerdam’s 
work. 
He showed also the food canal and the tubules connected 
