THE VASCULAR SYSTEM 191 



A F. cordis from the ventricle enters the right ductus Cuvieri on 

 its ventral aspect at the right margin of the ventricle. 



3. Functional. 



The problem of whether there is any separation of the oxygenated 

 and de-oxygenated blood in the Salamander is a vexed one. As 

 already mentioned, Briicke — who was one of the earliest workers to 

 attack the question — came to the conclusion, as the result of injection 

 experiments, that in all probability no such separation did occur, 

 while Suchard, who followed him, thought that there was some slight 

 separation. Noble (1925), as the result ofinjecting Indian ink into the 

 pulmonary veins of a number of Amphibia, both Urodeles and Anura 

 — but not Salamandra — came to the conclusion that in those animals 

 which possessed lungs, two auricles and a septum bulbi, the oxygen- 

 ated and de-oxygenated blood remained distinct, and that the former 

 never entered the pulmonary arch, whereas in those Amphibia which 

 are devoid of lungs, and in which the septum bulbi and inter-auri- 

 cular septum have also atrophied to a greater or lesser extent, no 

 such separation could be demonstrated. He therefore ascribed to 

 the septum bulhi the important function of bringing about this separa- 

 tion. All injection experiments are open, to a varying extent, to the 

 objection that it is impossible to execute them without causing 

 traumatic shock to the heart, which is very sensitive to such stimulus. 

 It is, therefore, difficult to be sure that one is obtaining a normal 

 systolic rhythm under these conditions. Noble's results are con- 

 sistent, and would seem to be as free as possible from this objection. 

 Nevertheless they are susceptible of another explanation than that 

 which he puts forward. 



Ziillich (1930) gives a detailed and tolerably complete account 

 of the course of the blood through the heart in Salamandra, and con- 

 cludes that while the blood from the right and left auricles does to 

 a large extent remain distinct as it passes through the heart, the sep- 

 tum bulbi is in no way responsible for this — a conclusion with which the 

 present writer is in agreement. A careful examination of the structure 

 of the bulbus cordis and truncus arteriosus makes it impossible to 

 conceive that the septum bulbi can have any effect whatever on the 

 separation of the two kinds of blood in the Salamander, although it 

 probably has in Rana and other Anura where it extends farther into 

 the truncus impar.^ 



' Since this was written a paper has appeared by Vandervael (1933) setting forth con- 

 clusions different from those given here. His experiments consisted of observing the 

 circulation of the blood through the heart and arterial trunks of the Frog by means of 



