114 



NORMAL HISTOLOGY. 



spleen, and growth from the blood-platelets, or haematoblasts c 

 Hayem, have been advanced from time to time as additional source 

 of origin of the red blood-corpuscles. Without entering upon 

 detailed critical consideration of the evidence supporting these view: 

 it may be stated that, excepting the spleen, they lack the conclush 

 proof of unimpeachable direct observation. Concerning the rel; 

 tions of the ' ' hsematoblasts' ' much confusion exists in consequenc 

 of the application of the term to different objects by various writer 

 The formative processes within the red bone-marrow may be r 

 garded, in the light of our present knowledge, as the most importai 

 source of the new red blood-corpuscles produced throughout lif< 

 After severe hemorrhage, it is probable that the spleen may assun 

 the role of a blood-forming organ. 



Mention may be made in this place of the problematic organs tl 

 so-called arterial glands, which include the coccygeal and caret 

 glands. 



The first of these, the glandula coccygea, or Luschka's glan 

 occurs near the tip, in front of the apex, of the coccyx, associat< 

 with the middle sacral artery, which contributes the blood-vesst 

 largely forming its pea-sized mass. The carotid gland lies at tl 

 bifurcation of the common carotid artery, frequently between tl 

 resulting branches, and appears as a somewhat flattened ovo 

 nodule. 



These peculiar bodies are similar in structure, both consistin 

 of dense capillary net-works enclosing irregular groups of grar 

 ular polyhedral cells, whose presence suggested the once suppose 

 glandular nature of the organs. The entire plexiform mass is investe 

 by connective tissue, fibrous septa penetrating between the va: 

 cular territories, at the periphery of which course the veins. Ni 

 merous non-medullated nerve-fibres are also present. 



The true nature and function of these rudimentary organs are e 

 tirely unknown, and probably will remain so until the embryology ( 

 these bodies is better understood. Their apparent close relation 1 

 the sympathetic has led many to regard these organs as affiliate 

 with this nervous system ; hence they are sometimes designated < 

 " sympathetic ganglia." 



