364 ARTHUR WILLIAM MEYER 



forms of nodes. SiiH'(> Pill/ found these mixed forms; that is 

 nodes a ])ortion of which contained mainly blood and the rest 

 only lymphatic tissue; in animals several years old he assumed 

 a continued new formation. According to Piltz's conception 

 lymi)h vessels grow into the node after the sinuses (sic) have 

 been replaced by lymph cells and the node has been converted 

 into a lymph node. Piltz also regarded the blood sinuses as 

 dilated capillaries originally , i.e., during early development — but 

 nevertheless thought it unlikely that hemal nodes were ever in 

 connection with the vascular systeni! 



Tixier and Duval, '10 also described, in vaccinated calves, 

 certain glands which had the general structure of lymph glands 

 but which possessed no lymphatics. They found four, eight 

 or ten or even more, dark reddish nodes imbedded in the thy- 

 mus or in contact with its cervical or cardiac portions or within 

 the mediastinum. It is significant, however, that these nodes 

 reminded them of similar nodes found previously near the thy- 

 mus in infants, and that those from the vaccinated calves con- 

 tained sinuses exactly like those in lymph nodes but larger. 

 These sinuses the authors considered as the beginning of veins 

 and surmised that the arteries open directly into the lymphoid 

 tissue. 



Schellhase, '11 reported that hemolymph nodes are commonly 

 present in bovines, sheep and goats in the tropics and reported 

 two cases in zebus in which innumerable nodes were found in 

 the interstitial tissue of the lungs. In one case these nodes 

 varied in size from the ''head of a pin to a lentil" while in the 

 other, they were as large as a bean. Their structure was said 

 to be typical — whatever that may mean — of hemolymph nodes 

 in all cases. 



The occurrence, location and structure of hemal nodes of the 

 domestic sheep, of guinea pigs, rabbits, cats, dogs, goats, et cet- 

 era, together with the occurrence and alleged experimental pro- 

 duction of supernumerary spleens were discussed in the previous 

 papers of this series (Meyer, '13 and '14). Hence the present 

 discussion will be limited to two species except in so far as 



