148 



THE BLOOD-GLANDS. 



fusion of heterogeneous blood ( 200). When many vessels are occluded, rupture of some small' 

 blood-vessels may take place. This explains the occurrence of slight, yet persistent haemorrhages, 

 which occur on the free surfaces of the mucous and serous membranes, and in the parenchyma 

 of organs, as well as in wounds. The blood coagulates with difficulty, and imperfectly. 



Transfusion of other Fluids. Other substances have been transfused. Normal saline solu- 

 tion (0*6 per cent. NaCl), or serum from the same species, aids the circulation in a purely 

 mechanical way (Ooltz), and it even excites the circulation (Kronecker). In severe anaemia this 

 fluid cannot maintain life (Eulenburg and Landois). The injection of peptone, even in moderate 

 amount, is dangerous to life, as it causes paralysis of the vessels (p. 32). 



The Blood-Glands. 



1031 



the hi 1 uni. 



Capsule. 



Trabecule. 



THE SPLEEN. Structure. The spleen is covered by the peritoneum, except at 

 Under this serous covering there is a tough, thick, elastic, fibrous capsule, which 



closely invests the organ and gives a covering to 

 the vessels which enter or leave it at the hilum, so 

 that fibrous tissue is carried into the organ along 

 the course of the vessels (fig. 119). [The capsule 

 cannot be separated without tearing the splenic 

 pulp.] Numerous trabeculse pass into the spleen 

 from the deep surface of the capsule, where they 

 branch and anastomose so as to produce a network 

 of sustcntacular tissue, which is continuous with 

 the connective-tissue, prolonged inwards and sur- 

 rounding the blood-vessels (fig. 120). Thus, the 

 connective-tissue in the spleen, as in other viscera, 

 is continuous throughout the organ. In this way 

 an irregular dense network is formed, comparable 

 to the meshes of a bath sponge. [This network 

 is easily demonstrated by washing out the pulp 

 lying in its meshes by means of a stream of water, 

 when a beautiful soft semi-elastic network or 

 framework of rounded and flattened threads is 

 obtained.] The capsule (fig. 119) is composed of 

 interlacing bundles of connective-tissue mixed 

 with numerous fine fibres of elastic tissue and 

 some non-striped muscular fibres. 



Reticulum. Within the meshes of the trabecu- 

 lar framework there is disposed a very delicate 

 network or reticulum of adenoid tissue, which, 

 with the other coloured elements that fill up the 

 meshes, constitutes the splenic pulp (fig. 121 ). The 

 reticulum is continuous with the fibres of the 

 trabecular [If a fine section of the spleen be 

 " pencilled " in water, so as to remove the cellular 

 elements, the preparation presents much the same 

 characters as a section of a lymph-gland similarly treated, viz., a very fine network of adenoid 

 tissue, continuous with, and surrounding the walls of, the blood-vessels. The spaces of this 

 tissue are filled with lymph-and blood-corpuscles. ] 



The pulp is a dark reddish-coloured, semi-fluid material, which may be squeezed or washed 

 out of the meshes in which it lies. It contains a large number of coloured blood-corpuscles, 

 and becomes brighter when it is exposed to the action of the oxygen of the air. 



Blood-Vessels and Malpighian Corpuscles. The large splenic artery, accompanied by a vein, 

 splits up into several branches before it enters the spleen. Both vessels and their branches 

 are enclosed in a fibrous sheath, which becomes continuous with the trabecular The smaller 

 branches of the artery gradually lose this fibrous investment, and each one ultimately divides 

 into a group or pencil of arterioles or penicilli, which do not anastomose with each other. [Thus 

 each branch is terminal a condition which is of great importance in connection with the patho- 

 logy of embolism or infarction of the vessels of the spleen.] At the points of division of the 

 branches of the artery, or scattered along their course, are small oval or globular masses of 

 adenoid tissue ( K V to ^ inch in diameter), the Malpighian corpuscles. [These bodies are 

 visible to the naked eye as small, round, or oval white structures, about the size of millet seed, 

 in a section of a fresh spleen. They are very numerous [70,000 in man] and are readily 

 detected in the dark reddish pulp. One must be careful not to mistake sections of the trabeculse 



Malpighian 

 corpuscles. 



Splenic pulp. 



Trabecula. 



Blood-vessel in 

 a trabecula. 



(HI 



Fig. 119. 



Sectiou of human spleen x 10 



times. 



