Section 73. We may mention here the structure of the spleen (Figure 1, Sheet 1). It consists of a connective tissue and muscular coating, with an internal soft matrix much resembling botryoidal tissue, traversed by fibrous trabeculne (= beams, planks) containing blood-vessels, and the whole organ is gorged with blood, particularly after meals. The consideration of its function the student may conveniently defer for the present. Section 74. Here also, we may notice the lymphatics, a series of small vessels which return the overflow of the blood serum from the capillaries, in the nutrition of the tissues in all parts of the body, to the thoracic duct (see Section 36), and the general circulation. At intervals their course is interrupted by gland-like dilatations, the lymphatic glands, in which masses of rapidly dividing and growing (proliferating) cells occur, of which, doubtless, many are detached and become, first "lymph corpuscles," and, when they reach the veins, white blood corpuscles. 5. _The Skeleton_ Section 75. We are now in a position to study the rabbit's skeleton. We strongly recommend the student to do this with the actual bones at hand-- they may be cleared very easily in a well-boiled rabbit. This recommendation may appear superfluous to some readers, but, as a matter of fact, the marked proclivity of the average schoolmaster for mere book-work has put such a stamp on study, that, in nine cases out of ten, a student, unless he is expressly instructed to the contrary, will go to the tortuous, and possibly inexact, descriptions of a book for a knowledge of things that lie at his very finger-tips. We have not written, this chapter to give a complete knowledge of the skeleton, but simply as an aid in the actual examination of the bones. Section 76. We may take the skeleton under five headings. There is the central axis, the chain of little bones, the vertebrae, threaded on the spinal cord (see Figure 1 and Section 1); the thorax, the box enclosed by ribs and sternum; the fore-limb and bones connected with it (pectoral girdle and limb), and the hind-limb and bones connected with it (pelvic girdle). Finally there is the skull, but following the London University syllabus, we shall substitute the skull of the dog for of that of the rabbit, as more typically mammalian (Section 4).