. The bee-keeper's guide : or Manual of the apiary . Bee culture; Bees. Organs of Circulation. 67 and receives the blood at valvular openings (Fig. 19, o) along its sides which only permit the fluid to pass in, when by contraction it is forced toward the head and emptied into the general cavity. Thus the heart only serves to keep the blood in motion. There are no vessels to carry the blood to the various organs, nor is this necessary, for the nutritive fluid every- where bathes the digestive canal, and thus easily receives Fig. Portion oj Henri of an Insect, ajler Paclard. li Heart m Musc
. The bee-keeper's guide : or Manual of the apiary . Bee culture; Bees. Organs of Circulation. 67 and receives the blood at valvular openings (Fig. 19, o) along its sides which only permit the fluid to pass in, when by contraction it is forced toward the head and emptied into the general cavity. Thus the heart only serves to keep the blood in motion. There are no vessels to carry the blood to the various organs, nor is this necessary, for the nutritive fluid every- where bathes the digestive canal, and thus easily receives Fig. Portion oj Henri of an Insect, ajler Paclard. li Heart m Muscles, o Openings. nutriment, or gives waste by osmosis; everywhere sur- rounds the trachese or air-tubes—the insect's lungs—and thus receives that most needful of all food, oxygen, and gives the baneful carbonic acid; everywhere touches the various organs, and gives and takes as the vital operations of the animal require. The heart, like animal vessels, generally, consists of an outer serous membrane, an inner, epithelial coat, and a middle muscular layer. Owing to the opaque crust, the pulsations of the heart cannot generally ne seen; but in some transparent larvae, like man}' maggots, some parasites —those of our common cabbage butterfly show this admir- ably—and especially in aquatic larv£E, the pulsations are plainly visible and are most interesting objects of study. The heart, as shown by Lyonnet, is held to the dorsal wall by muscles (Fig. 19, ni). Beneath the heart are mus- cles which, to quote from Girard, form a sort of horizontal diaphragm (Fig. 20, <^), which as Graber shows contract and thus aid Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Cook, Albert John, 1842-1916. Chicago, Ill. : George W. York & Co.
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectbees, bookyear1894
