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 1 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 each ring of the body, 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 oesophagus, 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- 

 gra])h 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 each 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 



