xiv THE LYMPH 553 



the digestive secretion. It seems probable, in fact, from the 

 theoretical standpoint that the congested spleen, by means of the 

 nutritive substances freshly absorbed from the digestive apparatus, 

 produces and pours into the blood substances that favour in some 

 way the formation of the enzymes which are the active principles 

 of the gastric (Baccelli) or of the pancreatic juice (Schiff, Herzeii). 

 We shall return to this point iu another connection. It also 

 appears highly probable that the spleen and perhaps the lymphoid 

 organs and tissues in general serve as magazines or reserve stores 

 for the proteins deriving from digestion, and which cannot be 

 immediately utilised by the tissues, just as the liver stores up the 

 carbohydrates that accumulated there, in the form of glycogen. In 

 favour of this hypothesis we have the fact of the marked reduction 

 which the spleen and lymph glands undergo during inanition 

 (Fredericq). 



Another important phenomenon observed in clinical practice is 

 the temporary swelling exhibited by the spleen in many of the 

 infective diseases that are accompanied by fever. In malarial 

 fevers the enlargement of the spleen increases constantly, with 

 repeated attacks, until it becomes permanent and may reach 

 considerable proportions, either by the accumulation of the 

 malarial parasites and their products, or, as is probable, by 

 paralysis of all the muscular elements of the organ. We have 

 seen that the lymphatic glands swell by a similar process under 

 similar morbid conditions, and that this process is of great import- 

 ance in arresting the infective germs, and rendering the toxic 

 substances which they produce innocuous. The spleen may also 

 be regarded as an organ of defence against infective agents, which 

 harmonises perfectly with the fact of the presence of numerous 

 phagocytes contained in the splenic pulp. 



The contractility of the spleen has been tested by direct stimula- 

 tion of the organ, and by excitation of the peripheral nerves that 

 run to it, as also by direct or reflex stimulation of the nerve centres. 



If the spleen of an anaesthetised dog is exposed, the contact 

 of the air at first produces a contraction of the organ, which 

 disappears after some time, its surface becoming supple again, and 

 dark red. On then bringing together the electrodes from an 

 induction coil and applying them to any point on the organ, a 

 hollow and blanching will be produced in consequence of local 

 contraction, which drives out the blood. On running the 

 electrodes over the surface of the organ, grooves and white lines of 

 any form desired can be traced (Briicke). The human spleen has 

 less contractility than that of the dog, cat, and many other 

 animals, owing to the smaller number of muscle cells contained in 

 the capsule and the trabeculae; contraction can, however, be 

 determined by the percussion method, after faradisation of the 

 organ through the skin (Botkin). 



