66 ORGANS OF DIGESTION. 



and not another, of which, in my own observations, I have had 

 an example. The veins, on the contrary, do anastomose, not 

 only as regards the collateral branches of the same primitive 

 trunk, but also by the collateral branches of different trunks. 

 These anastomoses are not large. The arteries terminate free- 

 ly in the veins, as may be proved by fine injections, and by the 

 microscope. 



The mass of the spleen, upgn superficial examination, seems 

 to consist in a dark brown pulp, which is contained in the cells 

 dividing the cavity of the internal coat, and may be easily de- 

 monstrated by tearing the spleen, and scraping it with a knife 

 handle. MM. Assolont and Meckel believe, that blood, besides 

 being in the arteries and veins, is placed in a state of particular 

 combination and of intimate union with the other organic ele- 

 ments of this viscus, and with a large quantity of albumen ; and 

 that this combination of the blood forms the dark brown pulp 

 alluded to. The great quantity of albumen in the pulp, is rea- 

 dily proved by the hard coagulum which it forms, when steeped 

 in alcohol. But a question has arisen whether the pulp be ex- 

 travasated in the cells which contain it, or whether it be still re- 

 tained in the extremities of the blood vessels. Superficial exa- 

 mination is in favour of the first, but M. Marjolin denies it on 

 the following grounds; that injections, cautiously made, pass 

 immediately from the arteries into the veins; and that the 

 spleen, when successfully injected and frozen, does not exhibit 

 ice in the interstices of its vessels, while their capillary ramifi- 

 cations distended by the injected fluid, are distinctly seen. 

 From these he concludes that the glandular structure of the 

 spleen is formed essentially of arterial and venous capillary ves- 

 sels with very delicate and extensible coats; that they commu- 

 nicate with one another without the intermedium of any cell; 

 and that the extreme tenuity of these vessels, and their exten- 

 sibility in every direction, are sufficient to explain the augmen- 

 tation of volume of the spleen, under certain circumstances, as 

 well as the promptitude of its diminution under others. 



In addition to this pulp, many observers have met in the 

 spleen with an abundance of rounded corpuscles, varying in 

 size from an almost imperceptible magnitude to a line or more 

 in diameter.* They are of a gelatinous consistence, soft, gray- 



* Malpighi, Ruysch, Hewson, Home, Dupuytren, Meckel, Sec. 



