92 ZOOLOGY 



function. A paper by Brambell, who was a pupil of Gatenby (15), 

 on yolk formation in 1924 has formed the basis of all subsequent 

 investigations in that direction, and Bowen, who has contributed 

 largely to our knowledge of the Golgi apparatus, says at the end 

 of a review of the knowledge of that cell element (12, 1927) that 

 the position is hopeful in that certain definite problems are 

 emerging. 



In the protozoa most of the work centres round the establish- 

 ment of homologies of protozoal cell elements with those found in 

 higher forms, and therefore is closely related to pure cytology. 

 The discovery of a neuro-fibrillar structure in many protozoa is of 

 outstanding importance from the purely morphological point of 

 view as well as from the physiological. 



THE STRUCTURE OF THE GOLGI APPARATUS 



The discovery of the reticular apparatus in the nerve cells of 

 vertebrates by Golgi and his school of workers forms the basis of 

 all investigations in this direction. This is so much the case that 

 even recent conceptions of the structure and general appearance 

 of this cell organ have been coloured by Golgi's ideas and by 

 theories like that of Holmgren's " trophospongium," which were 

 put forward at that time and which many workers believed were 

 accepted by Golgi himself. Golgi described the apparatus as a 

 reticulum or network, while Holmgren conceived of a canalicular 

 system following the lines of the network, but essentially watery 

 and " tubular " in character. Holmgren's views were disproved, 

 but the possibility of internal vacuoles or canaliculae was always 

 present in many investigators' minds. This was complicated 

 by the difficult techniques, often capricious in their action, 

 employed and also by the different forms in which the Golgi 

 apparatus was found in other cells and animals. Even as late as 

 1917 we find that the identity of Golgi apparatus in Helix is under 

 discussion by Gatenby, a discussion reopened in 1926 by Parat 

 and others, although not very satisfactorily. It was this very 

 divergence in form now recognised as one of the characteristic 

 properties of the Golgi apparatus which proved to be the chief 

 difficulty in the way of earlier workers. 



