s. In the female
(Fig 9) there is a shallow external orifice which is continued into
the bladder by a short canal, the urethra, the remaining urinary
surface being the same as in the male; the external opening also is
extended into the short, wide tube of the vagina, which is continuous
with the canal of the uterus. This canal is continued on both sides
into the Fallopian tubes or oviducts. There is thus in the female a
more complete separation of the urinary and the genital surfaces than
in the male. Practically all of the waste material of the body which
results from cell activity and is passed from the cells into the fluid
about them is brought by the blood to the kidneys, and removed by
these from the blood, leaving the body as urine.

[Illustration: FIG. 8.--A LONGITUDINAL SECTION THROUGH THE MIDDLE OF
THE BODY SHOWING THE EXTERNAL AND INTERNAL SURFACES AND THE ORGANS.

1. The skull.
2. The brain, showing the convolutions of the gray exterior in which
the nerve cells are most numerous.
3. The white matter in the interior of the brain formed of nerve
fibres which connect the various parts of this.
4. The small brain or cerebellum.
5. The interior of the nose. Notice the nearness of the upper part of
this cavity to the brain.
6. The hard or bony palate forming the roof of the mouth.
7. The soft palate which hangs as a curtain between the mouth and the
pharynx.
8. The mouth cavity.
9. The tongue.
10. The beginning of the gullet or oesophagus.
11. The larynx.
12. The windpipe or trachea.
13. The oesophagus.
14. The thyroid gland.
15. The thymus gland or sweetbread.
16. The large vein, vena cava, which conveys the blood from the brain
and upper body into the heart.
17-25. Lymph nodes; 17, of the neck; 25, of the abdomen.
18. Cross section of the arch of the aorta or main artery of the body
after it leaves the heart.
19. The sternum or breast bone.
20. The cavity of the heart.
21. The liver.
22. The descending aorta at the back of the abdominal cavity.
23. The pancreas.
24. The stomach.
26. Cross section of the intestines.
27. The urinary bladder.
28. The entrance into this of the ureter or canal from the kidney.
29. Cross sections of the pubic bone.
30. The canal of the urethra leading into the bladder.
31. The penis.
32. The spinal cord.
33. The bones composing the spinal column.
34. The sacrum. The space between this and No. 29 is the pelvis.
35. The coccyx or extre