FffiTAL LUNGS. 623 



small proportion to be submitted to chemical analysis. But the 

 thymic fluid of the foetal calf, which exists in great abundance, gave 

 the following analytical* results: one hundred parts of the fluid 

 contained sixteen parts of solid matter, which consisted of, 



Incipient fibrine, 



Albumen, 



Mucus, and muco-extractive matter, 



Muriate and phosphate of potass, 



Phosphate of soda, 



Phosphoric acid, a trace. 



The Arteries of the thymus gland are derived from the internal 

 mammary, and from the superior and inferior thyroid. 



The Veins terminate in the left vena innominata, and some small 

 branches in the thyroid veins. 



The Nerves are very minute, and are derived chiefly through the 

 internal mammary plexus, from the superior thoracic ganglion of the 

 sympathetic. Sir Astley Cooper has also seen a branch from the 

 junction of the pneumogastric and sympathetic pass to the side of the 

 gland. 



The Lymphatics terminate in the general union of the lymphatic 

 vessels at the junction of the internal jugular and subclavian veins. 

 Sir Astley Cooper has injected them only once in the human foetus, 

 but in the calf he finds two large lymphatic ducts, which commence in 

 the upper extremities of the glands, and pass downwards, to terminate 

 at the junction of the jugular and subclavian vein at each side. These 

 vessels he considers the " absorbent ducts of the glands ; ' thymic 

 ducts ;' they are the carriers of the fluid from the thymus into the 

 veins." 



Sir Astley Cooper concludes his anatomical description of this gland 

 with the following interesting physiological observations: 



" As the thymus secretes all the parts of the blood, viz. albumen, 

 fibrine, and particles, is it not probable that the gland is designed to 

 prepare a fluid well fitted for the fetal growth and nourishment from 

 the blood of the mother, before the birth of the foetus, and, conse- 

 quently, before chyle is formed from food? and this process continues 

 for a short time after birth, the quantity of fluid secreted from the 

 thymus gradually declining as that of chylification becomes perfectly 

 established." 



FCETAL LUNGS. 



The Lungs, previously to the act of inspiration, are dense and solid 

 in structure, and of a deep red colour. Their specific gravity is greater 

 than water, in which they sink to the bottom; whereas lung which has 



* This analysis was conducted by Dr. Dowler of Richmond. 



