DIGESTIVE ORGANS AND THEIR ANATOMY. 301 



by the fact that the spleen may be taken out of an animal 

 without in any serious way inconveniencing it. It shows a 

 slight connection with the process of digestion in the fact 

 that soon after a meal the spleen becomes materially larger, 

 then contracts again during the fasting period. In addition 

 to these meal pulsations, observers have noticed that it un- 

 dergoes at all times slight contractions and expansions. 

 They have been stated by some to be at the rate of about 

 one expansion per minute. These secondary expansions are, 

 however, quite slight, and may be due to slight changes in 

 blood pressure. Various functions have been ascribed to 

 it. It has been supposed that red corpuscles were formed 

 here. This is true during foetal life and for a short time 

 after birth, but there is really no evidence at all for the view 

 that in adult life red corpuscles are formed here. Then, on 

 the other hand, it has been believed by many to be a place 

 where red corpuscles are destroyed. In evidence of this 

 fact is cited the observation just mentioned, that certain 

 cells of the spleen frequently have in their interior red cor- 

 puscles in all stages of disintegration. A further fact which 

 helps to support this view is the large proportionate amount 

 of iron which is found in the spleen, and it has been be- 

 lieved that this iron comes from the destruction of the iron- 

 containing-hsemoglobin of red corpuscles. While there 

 seems, therefore, at present much probability that this view 

 is the correct one, it is not yet an undisputed fact. The 

 ability to produce new white corpuscles has been ascribed 

 to the spleen. This is no doubt true. The presence of 

 much lymphatic tissue in the spleen would make readily 

 possible the formation of new white corpuscles just as in all 

 other lymphatic tissue. Recently the view has been ad- 

 vanced that in the spleen there is formed a kind of ferment 

 which when it reaches the pancreas (through the blood) 

 changes the trypsinogen contained in this gland into the 

 trypsin. There is so little evidence to support this view 

 that it has been accepted by practically no physiologists of 

 any note. In short, w*e may say of the function of the spleen, 



