OBSERVATIONS UPON THE SPLEEN. 121 



and respiration are sluggish, the blood-corpuscles few in numbers, the temperature 

 low, the metamorphosis of the elements of their structure slow, and the intellect 

 and all the life actions correspondingly feeble. 



If the function of the spleen be the construction, destruction, and elaboration 

 of some of the important elements of the blood, why is it so small and insig- 

 nificant in birds, and of such great relative magnitude in many cold-blooded 

 animals ? Is it possible that an organ, which, in many Ophidians, Chelonians, 

 and Birds, weighs only a few grains or a small fraction of a grain, can exert any 

 important influence upon the physical properties and chemical constitution of the 

 blood ? Do not these facts show conclusively that we do not understand the func- 

 tions of the spleen ? 



Mr. Gray 1 supposes that one office of the Malpighian corpuscles is to store up 

 nutritive matter when there is a surplus of alimentary materials ; to be restored 

 again to the blood when there is a deficiency of these elements. It is, however, 

 difficult to conceive, how nutritive matter of any importance could be stored up 

 in the Malpighian corpuscles of organs, weighing a few grains or only fractions 

 of a grain. The amount accumulated in such organs would be microscopic in its 

 character, and not much more than the hundredth part of a grain. 



Even in warm-blooded animals the amount of albuminous compounds contained 

 in the Malpighian corpuscles of the spleen is insignificant, and unworthy of notice 

 when compared with that contained in the circulatory apparatus, the capacious 

 reservoir of the nutritive materials. The circulatory apparatus of an adult man 

 contains, according to the most recent and reliable calculations, about twenty-two 

 pounds of blood, whilst the Malpighian corpuscles of the spleen are capable of 

 containing only a few grains. 



"Would nature construct an organ, an important office of which would be to 

 store up a few grains of nutritive matter, whilst the circulatory system contains 

 more than ten thousand times the amount? 



Mr. Gray instituted a valuable series of researches upon the effects of diet upon 

 the spleen of Cats, Rabbits, and Rats, and found that this organ increases during 

 active nutrition. As far as my observations have extended this phenomenon does 

 not occur in cold-blooded animals. 



The spleens of Salt-water Terrapins (Emys terrapin) and of Yellow-bellied Terra- 

 pins (Emys serrata), which had been starved and deprived of water for a great 

 length of time, and then transferred to a tub of water and abundantly supplied with 

 vegetable food, did not exhibit any increase in weight. I have also observed, in 

 numerous instances, that the spleen of cold-blooded animals does not act as a diver- 

 ticulum for any surplus water or nutritive materials in the circulatory apparatus. 



The spleens of many carnivorous Chelonians, whose circulatory apparatus was so 

 filled with blood consequent upon a change of diet, that aqueous albumino-saline 

 effusions took place into the cellular tissue, and all the cavities, presented no increase 

 in size or weight. 



The spleens of Ophidians, which are voracious and swallow large masses of flesh, 



1 The Structure and Use of the Spleen, by Henry Gray, F. R.S. London, 1854. 

 16 



