STUDIES IN COMPARATIVE ANATOMY.--No. III. THE COCKROACH. CHAPTER I. WRITINGS ON INSECT ANATOMY. Marcello Malpighi. 1628–1694. Jan Swammerdam. 1637–1680. Pierre Lyonnet. 1707–1789. Hercule Straus-Dürckheim. 1790–1865. The lovers of minute anatomy have always been specially attracted to Insects; and it is not hard to tell why. No other animals, perhaps, exhibit so complex an organisation condensed into so small a body. We possess, accordingly, a remarkable succession of memoirs on the structure of single Insects, beginning with the revival of Anatomy in the 17th century and extending to our own times. The most memorable of these Insect-monographs bear the names of Malpighi, Swammerdam, Lyonnet, and Straus-Dürckheim. _Malpighi on the Silkworm._ Malpighi’s treatise on the Silkworm (1669) is an almost faultless essay in a new field. No Insect--hardly, indeed, any animal--had then been carefully described, and all the methods of work had to be discovered. “This research,” says Malpighi, “was extremely laborious and tedious” (it occupied about a year) “on account of its novelty, as well as the minuteness, fragility, and intricacy of the parts, which required a special manipulation; so that when I had toiled for many months at this incessant and fatiguing task, I was plagued next autumn with fevers and inflammation of the eyes. Nevertheless, such was my delight in the work, so many unsuspected wonders of nature revealing themselves to me, that I cannot tell it in words.” We must recall the complete ignorance of Insect-anatomy which then prevailed, and remember that now for the first time the dorsal vessel, the tracheal system, the tubular appendages of the stomach, the reproductive organs, and the structural changes which accompany 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 eyes and cautious judgment. The descriptions are brief and simple, the figures clear, but 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. Had the tract De Bombycibus been the one work of its author, this would have kept his memory bright, but it hardly adds to the fame of the anatomist who discovered the cellular structure of the lung, the glandular structure of the liver and kidney, and the sensory papillæ of the skin, who first saw the blood-corpuscles stream along a vessel, who studied very early and very completely the minute structure of plants and the development of the chick, and whose name is rightfully associated with the mucous layer of the epidermis, the vascular tufts of the kidney, and the follicles of the spleen, as well as with the urinary tubules of Insects.