306 THE BLOOD. [CHAP. XXVII. 



that fluid into that "plastic" compound. This substance cer- 

 tainly first appears in the chyle and lymph, where these par- 

 ticles are found in great numbers floating in an albuminous fluid. 

 Nor does it appear in the chyle until after that fluid has passed 

 through the mesenteric glands, which furnish these particles in 

 large numbers. 



Dr. Carpenter regards the appearance of these colourless cor- 

 puscles or cells in the blood as a phenomenon in close analogy 

 with the development of cells in the albumen of the seed in the 

 vegetable kingdom, and in the yolk of the eggs of oviparous 

 animals, and he supposes that the office of these cells is to convert 

 crude alimentary materials into proximate principles, which again, 

 through the agency of cells, may be converted into, or may afford 

 the materials for the peculiar compounds which form the charac- 

 teristic ingredients of the secretions, or may pass into organised 

 tissue.* 



Of the Development and Decay of the J3lood- Corpuscles. It 

 seems to us that the view which Mr. Wharton Jones takes re- 

 specting the development of the blood-corpuscles, already described 

 at pp. 300, 301, affords the most simple and correct explanation of 

 the origin and development of these particles. According to it, the 

 lacteal and lymphatic systems may be regarded as the source 

 whence fresh supplies of blood-corpuscles are being continually 

 furnished to the blood at all periods of life. In the early embryo, 

 as well as in the adult, the process of the formation of the blood - 

 corpuscle would be the same, that is, the development of a nucleated 

 cell, which undergoes transformation into the coloured particle, the 

 steps of the process being successively granule cell, nucleated cell, 

 and coloured particle (Fig. 179). This view would lead us to regard 

 the system of lymphatic and mesenteric glands as the seat of an 

 unceasing generation of new particles which undergo their later 

 stages of transformation in the blood. And it is well worthy the 

 attention of Pathologists, as affording an explanation of the great 

 influence which (as we learn from experience) this extensive system 

 of glandular bodies exercises upon general nutrition. 



Prior to the formation of this glandular system and the deve- 

 lopment of the lymph and chyle-corpuscles, the blood particles are 

 derived as nucleated cells from the cells of the germinal membrane, 

 but they undergo essentially the same changes as in the more 



* Dr. Carpenter's remarks on this subject deserve the attentive perusal and 

 consideration of physiologists. Vid. Principles of Human Physiology, 153 

 1 /><). Third edition. 



