HEMOLYMPH NODES AND ACCESSORY SPLEENS 249 



The conclusions of Tizzoni are also contradicted by Vulpius 

 who found no enlargement of the lymph nodes and no accessory 

 spleens after splenectomy in rabbits and goats up to five months 

 after operation. Vulpius also called attention to the fact that 

 Tizzoni failed to produce accessory spleens in rabbits and that 

 Pouchet showed that animals possessing no lymph nodes can 

 survive splenectomy. 



From what has been said it is clear that although none of 

 these investigators possessed any reliable criterion for the differ- 

 entiation of lymph from hemolymph nodes yet the validity of 

 their experiments was absolutely dependent upon the possession 

 of such a criterion. Neither did most of them keep controls. 

 Vincent "In order to institute a fair comparison .... 

 studied the hemal lymphatic glands in a dozen normal dogs. 

 The average number found was 4 or 5." However, in a foot- 

 note Vincent (43) says: "I state this average with some diffi- 

 dence, as the variations were so great in different cases." But 

 even if the use of controls and a reliable means of differentiation 

 between l3anph and hemal nodes could be dispensed with this 

 cannot be said regarding reliable data on the occurrence of acces- 

 sory spleens in apparently normal dogs. Elsewhere^ it has been 

 reported that a large percentage {10-\-) out of an extensive series 

 of apparently normal dogs and cats possess accessory spleens 

 or true hemal nodes. This being the case it becomes highly 

 probable as Foa first suggested that the splenic nodules found 

 by Tizzoni, Eternod and Griffini on the peritoneum and great 

 omentum after splenectomy were present in these animals before 

 the operation. Morandi and Sisto for other reasons also sur- 

 mised that the newly-formed nodes reported by these investi- 

 gators were hemol3rmph nodes normally present in dogs. Besides 

 Tizzoni's investigations contradict his conclusions. Nevertheless 

 Warthin believed that these and the nodules mentioned by Hos- 

 ier and Winogradow were hemoljonph nodes which were newly- 

 formed from fat and not accessory spleens. It is interesting in 

 this connection to note that Roth who made the pathological 



^ Meyer, The occurrence of supernumerary spleens in dogs and cats, with 

 observations on corpora libera abdominales. Anat. Rec, Philadelphia, 1914. 



