SECT. 32.] 



VASCULAR GLANDS. 



still but little known. Those under 1 and 2, as also the follicles of 

 3, contain much protein and fat in their tissue; while, on the 



Fig. 30. 



A Malpighian corpuscle, from the spleen of the 

 ox; magnified 150 times, a. Wall of the cor- 

 puscle; 6. contents; c. wall of the artery on 

 which it is seated : d. sheath of the same. 



other hand, the rest of the paren- 

 chyma of the spleen contains 

 peculiar substances, not yet fully 

 investigated, which indicate an 

 energetic process of decompo- 

 sition. Their physiological func- 

 tions are just as little known ; 

 and it may suffice to mention 

 here, that in the spleen, the 

 thymus, the supra-renal capsules, 

 and pituitary body, it can only be 

 the blood which supplies them 

 with materials, and the blood- 

 vessels and lymphatics, which again take up the substance prepared 

 by the glands. In the follicles of the oral cavity and of the 

 fauces, the latter is effused into the larger recesses of these 

 organs, and ultimately into the cavities mentioned ; whilst, as to 

 the intestinal follicles, it is doubtful whether they secrete matter 

 into the intestine, or absorb it from the latter and discharge it 

 into the vessels. In the lymphatic glands, the lymphatic vessels 

 conduct their fluid into the glandular follicles and take it up 

 again from them, now rich in lymph-cells. The development of 

 the vascular glands is still very obscure ; yet this much appears 

 certain, that they are developed either from the fibrous layer of 

 the intestine, or from the same blastema which produces the sexual 

 glands. The change of material is very energetic in most of these 

 glandular structures, as is shown by their large quantity of blood, 

 and their liability to disease; but the pituitary and supra-renal 

 body may, perhaps, occupy a subordinate position in this respect. 



Literature. — A. Ecker, art. Blutgefussdriisen, iu Wagner's Handw. d. Phys., 

 vol. iv. 1840. 



