430 



THE DIGESTIVE APPABATUS IN MAMMALIA. 



BEANOH OF SPLENIC AKTEKT WITH ITS EAMI- 

 PIOATIONS STUDDED WITH MALPIGHIAN COR- 

 PUSCLES. 



are composed of red blood-globules and coloured corpuscles, either free or 

 included in cells. Sometimes unchanged blood-discs are seen included in 



a cell ; but more frequently the 

 ^'§- included blood-discs are altered 



both in form and colour. Besides 

 these, numerous deep-red, or red- 

 dish-yellow, or black corpuscles 

 and crystals, either single or aggre- 

 gated in masses, are seen diffused 

 throughout the pulp substance ; 

 these, in chemical composition, 

 are closely allied to the hsematine 

 of the blood. The colourless ele- 

 ments consist of granular matter; 

 nuclei, about the size of the red 

 blood-discs, homogeneous or gra- 

 nular in structure; and nucleated 

 ■vesicles in small numbers. These 

 elements form a large proportion of 

 the entire bulk of the spleen in well- 

 nourished animals ; whilst they 

 diminish in number; and occasion- 

 ally are not found at all, in starved 

 animals. The application of chemi- 

 cal tests shows that they are essen- 

 tially a proteine compound.) 



Malpighian corpuscles. — These 

 are contained, like the pulp, in the meshes of the fibrous framework, and are 

 enveloped by this pulp. Scattered along the track of the small arteries, 

 these corpuscles are visible to the naked eye, and appear as whitish closed 

 sacs, cells, and nuclei floating in a plasma. The 

 Malpighian corpuscles are constituted by the adven- 

 titious tunic of the arteries, in which lymphoid ele- 

 ments are accumulated at certain points. They 

 are therefore allied to the closed follicles of the 

 intestines. (These splenic or Malpighian corpuscles, 

 are round, whitish, semi-opaque bodies, glutinous 

 in consistence, and disseminated throughout the sub- 

 stance of the organ. They are more distinct in 

 early than in adult life or old age, and vary con- 

 siderably in size and number. From the manner 

 CLE, FKOM THE SPLEEN in which they are appended to the sheaths of the 

 OF THE ox. smaller arteries and their branches, they resemble 



1, External tunic, or mem- the buds of the moss-rose. Each consists of a mem- 

 ularcontent^s'^3*^Part ^ranous capsule, composed of fine pale fibres inter- 

 of a small artery ; \ ^^o^g i^i *U directions. The blood-vessels ramify- 

 Its sheath, derived from ing on the surface of the corpuscles, are the larger 

 the external tunic of the ramifications of the arteries to which the sacculus 

 spleen, with which the jg connected, and also of a delicate capillary plexus, 



corpuscle IS closely con . -i j. i.r, i. j- .i • i j? j.i 



nected. Similar to that surrounding the vesicles of other 



glands. These vesicles have also a close relation 

 with the veins, and the vessels begin on the surface of each vesicle through- 

 out the whole of its circumference, forming a dense venous mesh in which 



Fig. 218. 



A SINGLE SPLENIC COKPUS- 



