FIG. 1. Skin, Frog 2. Blood, Human 3. Do. Pigeon 4. Do. Proteus 5. Do. Tortoise 6. Do. Frog 7. Do. Fish 8. Human nail 9. Bone, Human 10. White fibrous tissue 11. Epithelial cells from tongue 12. Feather, Peacock 13. Spine, Hedgehog, transverse section 14. Pax-wax 15. Epithelial cells from nose 16. Bone, Ostrich 17. Feather, Shaft of Canary’s 18. Do. Wild Duck 19. Circulation of blood, Frog’s foot 20. Feather, Sparrow 21. Do. Cock’s tail 22. Fibre, crystalline lens of fish 23. Nerve 24. Muscle, Meat 25. Tooth, transverse section 26. Do. Longitudinal section 27. Sweat duct 28. Eye of Haddock 29. Myliobates, palate 30. Gristle, Pig 31. Pigment, Human eye 32. Do. Wing of Bat 33. Do. Shell of Prawn [Illustration: X.] A few words may be said, in the first place, as to the outfit. A very useful part of it is a walking-stick, to which can be attached either a net for capturing the larger forms of life, or a hook for collecting the weeds, to which many forms of great interest and beauty are attached (Fig. 15). The stick is telescopic, and can also have attached to it a bottle, which, put into the water at any desired spot,--say, amongst a clump of weeds, or near the bottom, upside down, and then suddenly reversed,--will bring away samples of the inhabitants of the neighbourhood. When these are sparsely distributed through the water, the latter may be concentrated by the use of a bottle round the neck of which is firmly tied a coarse calico bag, funnel-shaped, and supported by a wire ring, somewhat as shown in the illustration. Muslin is, however, too coarse for many organisms. This net is immersed in the water so that the ring is just above the surface, and one bottleful after another poured through. The water strains off, the organisms are left behind. The immersion is necessary to reduce the pressure to which delicate organisms would otherwise be subjected. When the bottle is full, or sufficiently concentrated as to its contents, the latter are poured into one of the ordinary collecting-bottles, of which half a dozen at least should always be taken. [Illustration: Fig. 15.] On reaching home, and as often as possible on the way, the corks should be removed, as these organisms soon use up the air in the water.