644 SCIENCE PROGRESS 



THE OOLGI AFFABATUS (Reginald James Lndford, Ph.D., B.Sc, 

 F.R.M.S., University College, London). 



Twenty-three years ago, the Italian histologist, Golgi, first described 

 in cells of the central nervous system a net-like structure which he called 

 the " interne reticulate apparato " (internal reticular apparatus). Since that 

 time a similar structure has been found to occur in all types of cells prepared 

 by appropriate methods, and has been called, after its discoverer, the Golgi 

 apparatus. 



There is considerable variation in the form of the apparatus in different 

 animals and also in the different tissues of the same animal. In nerve cells 

 of the higher animals it has the appearance of an irregular broken network, 

 but in most of the other cells of their bodies it consists of a small compact 

 network usually external to the nucleus. In Molluscs {e.g. Snail and Limpet) 

 it is usually represented by a number of small semilunar rods either scattered 

 throughout the protoplasm of the cells or else grouped together to form a 

 similar body as in the higher animals. Very commonly in insect cells, the 

 apparatus occurs in the forms of short rod-like granules without definite 

 arrangement (6), (These typical forms of the Golgi apparatus are shown in 

 Fig. I.) 



Generally the Golgi apparatus is only visible when cells have been pre- 

 pared by special techniques (see 4). It can, however, be seen in the living male 

 germ cells of the Garden Snail {Helix aspera) as small refractive rods, while 

 in some other cases it can be observed by special dark-ground illumination 

 methods. Some cells, especially those of Molluscs, show the apparatus when 

 stained in the living condition by dyes such as Janus green and Janus black, 

 and sometimes neutral red is effective. Usually, however, it is necessary to 

 kill the cell and impregnate the Golgi apparatus in a special manner (4). A 

 method commonly employed is to transfer the cell which has been killed in 

 a fixing and mordanting solution to silver nitrate solution, and afterwards to 

 a reducing solution. As the substance of the Golgi apparatus has a marked 

 afi&nity for silver stains, this procedure leaves the apparatus impregnated 

 with the silver. Another very effective method is to keep cells in dilute osmic 

 acid for two or three weeks. The Golgi apparatus then becomes black, owing 

 to the reduction of osmium tetroxide to the dioxide by its lipoid constituents. 

 It is interesting to find that if developing male germ cells of the snail be pre- 

 pared by both of these methods, the form of the Golgi apparatus is the same 

 in each case, and identical with its appearance in the living cell stained with 

 neutral red. 



Various researches have shown that the apparatus plays an important 

 part during periods of special cellular activity, and at certain stages of the life- 

 history of animals. One of the most comprehensive studies of the subject is 

 that which was carried out by Gatenby with the common pond snail, Limncea 

 stagnalis (5). Gatenby followed the behaviour of the Golgi apparatus from 

 the earliest stage of development of the germ cells to the formation of the 

 young embryo. The primitive germ cells contain a Golgi apparatus consisting 

 of a few semilunar rods grouped together at the side of the nucleus. The 

 female germ cell, as soon as it commences to mature, grows considerably in 

 size and undergoes a series of changes, the purpose of which is to prepare it 

 in such a way that on fusion with the mature male germ cell, it will develop 

 into a new organism. Very important for this purpose is the elaboration of 

 reserve food substances to provide the necessary energy and materials for 

 development. The Golgi apparatus is specially concerned with this process. 

 Each individual rodlet divides repeatedly, and, breaking away from the 

 original compact group, the rodlets spread throughout the cell, continually 

 dividing. From the very beginning of this activity certain of the rodlets 

 become concerned with the formation of yolk (9). A little globule of fatty 

 substance appears on the concave side of the roidlet, and this grows consider- 



