XIX] THE SPLEEN 155 



trabeculss very little developed, and a peculiar sheath around the 

 small arteries. 



In the frog's spleen, the trabeculse are very little developed, and 

 as in other lower vertebrates the arteries have no lymphoid sheath 

 or Malpighian corpuscles in connection with them. 



Iron may be tested for by the ferrocyanide method (cp. p. 184) 

 in sections of spleen which have been injected with and hardened in 

 alcohol. 



