XXX HISTORICAL INTRODUCTION 



In the end, however, he had to admit that he was wrong. First of all 

 he found that a vein might be accompanied by a pair of lymphatics, 

 and this raised doubts whether he might not be mistaken in some 

 cases. Finally he acknowledges that in the Salamander the blood- 

 vessels are enclosed by a double wall, and are hence morphologically 

 external to the lymph cavities, being related to them as the gut is to 

 the abdominal cavity. One valuable result of this otherwise futile 

 controversy was that it induced Rusconi to look closely at the 

 lymphatic system of Salamandra, which resulted in many valuable 

 facts being added to our knowledge of the system. 



It is surprising that up to this time no serious attempt had been 

 made to investigate the nervous system of the Salamander. The first 

 to do so was Fischer (1843), '^^o describes the cranial nerves in a 

 work which is remarkably accurate for the time it was written. He 

 did not find the fourth pair of nerves, and believed that its eye-muscle 

 was supplied by a branch from the trigeminus, but he was more 

 successful with the sixth nerve in spite of its small size. He was 

 unable to discover more than the slightest traces of the sympathetic 

 in the Salamanders, and believed that it was of much less importance 

 in them than in the Anura. This conclusion is not surprising in view 

 of the considerable difficulties which confront the investigator of the 

 sympathetic of Salamandra. Fischer's description and figure of the 

 fifth, seventh, and tenth cranial nerves are detailed and accurate. He 

 points out that the fifth and seventh nerves are separate in the Sala- 

 mander but fused in the Anura, and he correctly describes the 

 association of the glossopharyngeal with the vagus and its anasto- 

 mosis with the facial. He also understood the mutual relations of the 

 auditory and facial nerves. Meyer's work on the lymphatic system 

 of Amphibia (1845) ^^ largely a compilation from Panizza and Rus- 

 coni, but he found two pairs of anterior lymph hearts in the Sala- 

 mander which had not previously been seen. The longitudinal duct 

 coursing parallel with the inner margin of the kidney into which the 

 vasa efferentia open was first described by Bidder in 1846, and is 

 often referred to as Bidder's duct. The discovery of this duct made it 

 possible to solve the old riddle as to how the male sperm escaped from 

 the body, which had puzzled so many previous workers. The sperma- 

 tozoa themselves were re-described by Czermak in 1848. This 

 author, who had previously (1843) explored the differences between 

 S. maculosa and S. atra^ gives a remarkably accurate description, with 

 figures, of the complex spermatozoon of the Salamander, and he 

 even attempts to work out the details of spermatogenesis, as well 

 as the mechanics of the tail and its undulating membrane. Many 



