MALPIGHI, SWAMMERDAM, LEEUWENHOEK. 567 



pany transformation were observed, to give any adequate credit to 

 the writer of this masterly study. Treading ;i new path, he walks 

 steadily forward, trusting to his own sure eves and cautious judg- 

 ment. The descriptions are hrief 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 exte- 

 rior through button-hole shaped openings, and. internally, by an infini- 



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Fli 



"kiim Mai rii.iu'- Axatomy OF the Silkworm. 



tude 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 swell- 

 ings 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 oesophagus 

 and, on the dorsal surface, appearing as a more complex mass, or brain, 



