THE VASCULAR SYSTEM. 1 67 



The suprarenal bodies are small, somewhat bean-shaped 

 organs lying cephalad to the kidneys. An animal from 

 which they have been removed can live but a short 

 time. Their function is not known. They are sometimes 

 spoken of as suprarenal capsules. 



The above-named ductless glands occur in all mammals 

 in the same relative ocations. The anatomy of the 

 lymphatic system is also exceedingly similar throughout 

 the various orders of mammals. In some animals, espe- 

 cially man, the lymphatic glands are more numerous than 

 in the cat. The tracheal trunks are also wanting in man 

 and a right thoracic duct about two centimeters long is 

 usually present. A failure of the lymphatics to do their 

 work results in dropsy. 



PRACTICAL QUESTIONS AND SUGGESTIONS. 



1. Which of the four parts of the lymphatic system are visible in 

 your specimen? 



2. Describe size and number of lymphatic glands in the mesentery. 



3. Describe the location of lymph glands present in any other portion 

 of your specimen. 



4. How do you distinguish a lymph gland from other glands? 



5. What causes the lymph to flow in one direction only? 



6. W T hat is meant by afferent and efferent lymphatics? 



7. Which kind of blood-corpuscles are found within the lymph-vessels? 



8. From what regions does the thoracic duct receive the lymph? 



9. What glands receive the lymph from the thoracic limb? 



10. What glands receive the lymph from the pelvic limb? 



11. Describe location of spleen, thyroid and thymus glands, and 

 suprarenal capsules by naming the organs with which they are in contact. 



12. Draw a cross-section of the spleen and label all features visible. 



13. Draw a cross-section of the suprarenal body and label parts. 



14. Tell what you know of the functions of the ductless glands. 



15. What is a gland? 



