MAMMALS 



they are found only in fcetal life ; in some animals they persist much 

 longer {e.g., cat), while in others they may be permanent (ox, sheep, 

 Gerlach, 1848). In most Mammals the nerve plexus is more compli- 

 cated than in man. 



Since the early observations of Schlemm (1831) who demonstrated nerve- 

 fibres entering the cornea in stags and oxen, a considerable amount of work 

 has been done on this jDroblem. Most of the early work ^ is unconvincing, but 

 Cohnheim (1866-67), by introducing the gold chloride impregnation technique, 

 demonstrated their presence and complexity in the cornea of rabbits and guinea- 

 pigs, 3S well as in frogs and birds. This advance was followed by a large number 



455 







. t 4^- .V:* Vv'^^-ik*; 





Fig. 577. — The Xerves in the Corneal Endothelium in the Rabbit. 



Flat section, fixed in bromformalin, stained with del Rio Hortega's 

 " jDanoptic silver carbonate technique " (J. R. Wolter). 



of contributions which were assessed in the important papers of Waldeyer and 

 Izquierdo (1880) and Ranvier (1881) wherein the innervation of the cornea of 

 Fish, Amphibians, Reptiles and Birds as well as Mammals was assessed. The 

 introduction of the inethylene blue method of staining nerve fibres stimulated 

 a classical paper by Dogiel (1891) dealing with the monkey and man, while a 

 considerable number of Mammals was studied using the silver technique by 

 Crevatin (1903), Bielschowsky and Pollak (1904) and Cajal (1909). This work 

 was consolidated chiefly on Mammals by Virchow (1910), Agababow (1912) and 

 particularly Attias (1912). More recent studies using a variety of techniciues 

 including polarization and phase-contrast microscopy are those of Boeke and 

 Heringa (1924) (monkey), Nakajima (1930) (rabbit), Egorow (1934) (guinea- 

 pig), Boeke (1935) (monkey), Reiser (1935-37) (pig and guinea-pig), Borr 

 (1939) (rat), Peris (1947-49) (bull, sheep, rabbit, pig, cat, etc.), Rodger (1950) 



1 Bochdalek (1837-39) (larger Mammals), Pappenheim (1839-40) (oxen), Purkinje 

 (1845) (different Mammals), Kolliker (1848-66) (rabbits), Lusphka (1850) (rabbits), 

 Ciaccio (1863-81) (mice). 



