40 



Scientific Proceedings (78). 



therefore, cast upon the work of preceding investigators, notably 

 that of Tizzoni. 



During the years 1910-13 several series of experimental investi- 

 gations in regard to this point were carried out in my laboratory, 

 with results as yet unpublished. These are now presented here 

 in the form of a preliminary report. 



Results of Splenectomy. — Nine dogs were splenectomized and 

 examined as follows: Three one week after the operation; three 

 two weeks after, and three one month after. In no dog was there 

 the slightest change apparent in the lymph-nodes of any part of 

 the body. 



Five dogs were splenectomized and examined eight months 

 after the operation. In one dog the lymph-nodes and hemolymph- 

 nodes were larger than they had appeared to be at the time of 

 operation when these nodes were examined as carefully as they 

 could be. No new-formation of hemolymph-nodes was seen. 



Five dogs were splenectomized and examined eight and a half 

 months after the operation. No hyperplasia and no new-forma- 

 tion of lymph-nodes was seen. 



Five dogs were splenectomized and examined nine and a half 

 months after the operation. In one dog there was distinct en- 

 largement of lymphatic and hemolymph-nodes, but no new-forma- 

 tion. 



Results of Ligation of Splenic Veins. — In eight dogs the splenic 

 and gastrosplenic veins were ligated as completely as possible. 

 The animals were examined at periods of one week, two weeks, 

 three weeks, one month, three months, one year, one year and a 

 half, and two years after the operation. These animals were 

 carefully examined at the time of operation for the presence of 

 hemolymph nodes or accessory spleens in the gastrosplenic and 

 great omentum, as well as in the peritoneum and mesentery. 

 No changes in the lymph nodes and no new-formation of hemo- 

 lymph or splenic tissue was found in the first four dogs. In the 

 dog killed three months after the operation the prevertebral 

 lymph nodes and hemolymph nodes appeared to be slightly 

 enlarged. In the dog examined one year later the prevertebral 

 nodes were much enlarged, but no new formation was noted. 



In the dog examined eighteen months after ligation of the 



