THE VASCULAR SYSTEM 249 



(iii) Those receiving their blood from veins only — the lateral 

 plexuses covering the sinus endolymphaticus. 



Rex describes all the plexuses as venous, although it is quite easy 

 to trace the arterial connexions. He does not seem to have differen- 

 tiated clearly between arteries and veins. 



The roof of the diencephalon is peculiar in that it is comparatively 

 free from blood-vessels, but is bordered by four large plexuses. It 

 forms a sort of 'island'. 



The main venous exit is alongside the Vth nerve, anterior to the 

 auditory capsule. Smaller veins can usually be found leaving the 

 cranial cavity together with most of the other cranial nerves. 



LYMPHATIC SYSTEM 

 I. Historical. 



Panizza (1833) was the first thoroughly to investigate the lym- 

 phatics of the Salamander, and, while his account is somewhat 

 incomplete, and in one or two instances not quite correct, it is 

 nevertheless a classic piece of work. His use of mercury as a medium 

 for injection has been very sharply criticized by some later workers, 

 notably Rusconi and Meyer, on account of the weight of this 

 medium, which tends to deform the larger spaces. While this criti- 

 cism undoubtedly has some justification it resulted in Panizza's work 

 being discredited to an extent by no means deserved. Some five years 

 laterBazin(i 838— 9) published a resume of Panizza's work in French, 

 but his extract of the portion dealing with Salamandra is very brief. 



The work of the investigators immediately following Panizza 

 (Rusconi, Meyer, Calori) was almost entirely confined to the lymph- 

 atics of the viscera and the sub-vertebral trunks (DD. thoracici). 

 It is in this region that the distortion caused by mercury would be 

 most evident, and hence attention was concentrated upon it. 



J. Miiller (1833) ^^^ ^^ ^^^t to discover lymph hearts in the 

 Salamander, and he described four, an anterior pair just behind the 

 scapula and a posterior pair immediately caudad of the ilium. Meyer 

 (1845) confirms the existence of these hearts and describes and 

 figures an additional pair posterior to the scapula, making a total of 

 six pairs. In 1 884 Weliky showed that a whole row of segmentally 

 arranged contractile bladders exists, lying along the sulcus lateralis 

 between the dorsal and ventral body-muscles. He also investigated 

 the histology of the bladders, and found that they were provided with 

 muscles characteristic of lymph hearts. He says 'Die Muskeln der 

 Lymphherzen sind bei beiden untersuchten Thieren' {Salamandra 



