342 SECRETION. 



of blood. It must be admitted, also, that up to the present 

 time, no definite physiological ideas have followed the elabo- 

 rate microscopical and chemical examinations of the spleen. 

 There have been only two methods of inquiry, indeed, which 

 have promised any such results : First, a comparison of the 

 blood and lymph going into and coming from the spleen, 

 and an examination of the variations in the volume of the 

 organ during life ; and second, a study of the phenomena 

 which follow its extirpation in living animals. A review of 

 the literature of the subject will show that we have gained 

 but little positive information from either of these methods. 



The condition of the question of the influence of the 

 spleen upon the composition of the blood is well illustrated 

 in the last edition of Longet's elaborate work on physiol- 

 ogy. 1 This author quotes opinions of the highest authori- 

 ties, based chiefly upon microscopical investigations, some in 

 favor of the view that the blood-coi*puscles are destroyed, and 

 others arguing that they are formed in the spleen, while he 

 himself oifers no opinion upon the subject. 



Still there are certain established points of difference 

 between the blood of the splenic artery and of the splenic 

 vein. There can be no doubt of the fact that the blood 

 coming from the spleen contains a large excess of white cor- 

 puscles. Donne was the first to call attention to this fact, 2 

 and his observations have been confirmed by Gray, 3 and 

 many others. 4 It can by no means be considered settled, 

 however, that the function of the spleen is to form white 

 blood-corpuscles. In pathology, although great increase in 

 the leucocytes of the blood frequently attends hypertrophy 



1 LONGET, Traite de physiologic, Paris, 1869, p. 378. 



DONNE, Cours de microscopic, Paris, 1844, p. 99. Donne states that the 

 blood taken from the splenic veins presents nothing remarkable ; but on press- 

 ing out that contained in the tissue of the organ, the white corpuscles were 

 very abundant, and were even more numerous than the red. 



3 GRAY, The Structure and Use of the Spleen, London, 1854, p. 150. 



4 MILNE-EDWARDS, Lecons sur la physiologie, Paris, 185Y, tome i., p. 352, and 

 1862, tome vii., p. 256. 



