THE SPINNING ORGANS. 51 
exterior spools of the spinning field are always bent a little towards the 
centre. The spider, of course, possesses the power of regulating the flow 
of silk as to quantity, and can graduate it from the most delicate gossamer 
thread to the thickest blanket which is used for the rapid enswathment 
of insects. She can also play upon the special glands as occasion requires, 
-and extrude the viscid substance which forms along the spiral lines of an 
orbweb, or the variously colored silk used in cocooning. 
The field of comparative anatomy, and especially of histology, affords 
innumerable examples of the wonderful beauty of structure and adapta- 
tion of organs to the various uses of living creatures. But there are few 
objects better calculated to awaken admiration, even to the point of en- 
thusiasm, than the machinery by which the Orbweaver is enabled to 
prosecute her spinningwork. 
1 Meckel. 
