WHALEBONE. 



[ 686 ] 



WINTERE.E. 



the longitudinal section, viewed with this 

 power, the medullary lines are seen to con- 

 sist of a number of cells (PI. 17- fig- 30), 

 mostly arranged in single longitudinal series, 

 and, in dried whalebone, having a very dark 

 appearance by transmitted light, from the 

 presence within them of a large quantity of 

 pigment and air. These are the medullary 

 cells. The substance between the lines of 

 medullary cells exhibits very fine longitu- 

 dinal striae, and in parts, the ends of divided 

 laminae. 



On macerating whalebone for tw^enty-four 

 hours in solution of caustic potash, it be- 

 comes soft ; and on afterwards digesting it 

 in water, the cortical portion resolves itself 

 into numerous large transparent cells, from 

 1-230 to 1-310" in length, and from 1-500 to 

 1-330" in breadth (PI. 17. fig. 33). These 

 contain a variable number of granules of 

 pigment, of a deep brown colour, also some 

 small globules of fat, which are especially 

 numerous in those portions nearest the base 

 of the plate. These cells in the natural 

 whalebone are laterally compressed or flat- 

 tened, and the transverse axes of those sur- 

 rounding the medullary lines are arranged 

 tangentially to the latter ; whilst in the cor- 

 tical portions these axes are parallel to the 

 surface of the plate. The concentric lines 

 seen in a transverse section arise principally 

 from the pigment-granules within those 

 cells which surround the medullary cells 

 becoming arranged in a linear series, by the 

 flattening of the cells enclosing them. This 

 may be shown by treating a transverse sec- 

 tion of whalebone with caustic potash, and 

 then adding water, and watching its resolu- 

 tion into cells. As these expand, the inter- 

 rupted lines are seen also to expand as it 

 were, and to become resolved into a number 

 of distinct })igment-granules existing within 

 each cell. The lines seen in a longitudinal 

 section arise from the unequal refraction of 

 light by the laminae of compressed cells 

 surrounding the medullary lines. 



The medullary cells contain a large quan- 

 tity of pigment, as do also those compressed 

 cells which immediately surround them ; in 

 the former, these granules are frequently 

 aggregated. In the common dry whalebone 

 of commerce the medullary cells also con- 

 tain air, which has been mistaken for fat, 

 and hence the cells denominated fat- cells. 

 The air is readily displaced by liquids. Be- 

 tween the compressed cells minute cavities 

 containing air, sometimes assuming a linear 

 form, at others representing mere dots, are 



seen both in the transverse and longitudinal 

 sections ; these are distinguished by the dis- 

 placement of their contents. Hence ordi- 

 nary whalebone closely resembles hair or 

 horn in its structure, and the fibres which 

 are seen projecting from the margin of the 

 blades as found in commerce have a remark- 

 able similarity to hair (PI. 17. fig. 32). 

 Chemically, it consists of a proteine com- 

 pound, and is therefore coloured by Millon's 

 and Pettenkofer's test-liquids. 



Whalebone polarizes light like horn. 



BiBL. Donders, Mulder's Physiol. Che- 

 mie; he\\ma,nia, Phys. Chem.; Hunter, Phil. 

 Trans. 1787. 



WHEAT.— The starch of the grain of 

 wheat {Triticum vulgare and other species 

 and varieties) presents itself in the form of 

 delicate little flattish lenticular bodies, very 

 characteristic (PI. 36. fig. 8). Wheat is sub- 

 ject to various Blights, which are referred 

 to under that head, depending on the growth 

 of parasitic Fungi, especially Tilletia, 

 attacking the ear, Puccinia attacking the 

 straw, &c. In other cases the ear is found 

 infested with a minute worm (Anguillula 

 tritici) remarkable for its tenacity of life. 



WINGS, OF Insects. — The arrangement 

 of the veins or nerves of the anterior wings 

 of the Hymenoptera is sometimes used to 

 form the basis of systematic arrangement ; 

 and the several veins and interspaces have 

 received distinct names, which may be illus- 

 trated by means of PI. 27. fig. 11, represent- 

 ing the anterior wing of the humble-bee 

 {Bombus terrestris) (it must be remarked, 

 however, that in our figure, the nerves, a, d, 

 e, are not sufficiently distinguished); a, costal 

 nerve ; b, cubital nerve ; c, posterior margin 

 of wing, with the fold (w) for the attach- 

 ment of the hooks ; d, post-costal nerve ; 

 e, externo-medial ; f, anal ; the nerve be- 

 tween 3 and 10, the transverso-medial ; h, the 

 radial nerve ; k, the discoidal ; Z, the sub- 

 discoidal ; m, m,m, transverso-cubital nerves ; 

 s, stigma; 1, costal cell; 2, medial cell; 

 3, interno-medial ; 4, anal; 5, marginal; 

 10, first discoidal cell; 11, second ditto; 

 12, third ditto ; 13, first apical cell. 



See Insects, wings. 



BiBL. That of Insects; Jurine, Nou- 

 velleMethode, Szc; Shuckard, Trans. Entom. 

 Soc. i. 



WINTEREiE.— A section of the Dicoty- 

 ledonous family, Magnoliaceae (Drimys, 

 Tasmannia), remarkable for the character 

 of the elementary structure of the wood, 

 approaching closely to that of the Coniferae. 



