Quarterly Journal of Microscopical Science, Vol s2-65, 265-291, Copyright © 1921 by Company of Biologists

Memoirs: The Cytoplasmic Inclusions of the Germ-Cells. Part IX. On the Origin of the Golgi Apparatus on the Middle-piece of the Ripe Sperm of Cavia, and the Development of the Acrosome

¹ University College, London, and Senior Demy, Magdalen College, Oxford
² Assistant in Zoology and Comparative Anatomy, University College, London

(a) The Midd1e-piece Golgi Apparatus.

1. The middle-piece of the mammalian spermatozoon is formed froin part of the mitochondria of the spermatid which become grouped around a central rod or skeleton. Not all the mitochondria of the spermatid pass into the middle-piece, a certain proportion always sloughs off.

2. On the middle-piece of many mammalian spermatozoa there is a protoplasmic bead which can be seen in the fresh, and which, on fixation, stains in plasma dyes.

3. With formalin and silver nitrate techniques the protoplasmic bead is found to contain a number of argentophil platelets or rods, which impregnate exactly like the Golgi apparatus of younger sperm cells.

4. The spermatid of Cavia contains a Golgi apparatus consisting of an inner core of archoplasm, and a cortical region formed of curved plates and rods--the dictyosomes. With formalin-silver nitrate techniques, the Golgi apparatus either appears as a reticulum, or the whole cortex of the apparatus reduces the silver, and then appears homogeneous : with Mann-Kopsch techniques the individual dictyosomes are often very clearly marked.

5. At a stage when the spermatid is elongating the Golgi apparatus buds off a small part of itself. This part becomes separated from the main Golgi apparatus, and ultimately comes to lie in the middle-piece bead referred to in paragraph 2.

6. The rest of the Golgi apparatus of the ripening spermatozoon sloughs off.

7. While all the chromatinic substance of the young spermatid eventually goes to form the nucleus of the spermatozoon, only the majority of the spermatid mitochondria, and a very small part of the spermatid Golgi apparatus, form the representatives of these cell organs in the ripe spermatozoon.

8. Attention is drawn to the works of Lams and Doorme, van der Stricht, and Levi, where it has been shown that the whole middle-piece of the mammalian sperm (Cavia or Vespertilio) enters the egg at fertilization, but, so far as these authors could observe, thereafter remains inert, and is carried whole and haphazardly into one of the blastomeres.

(b) The Formation of the Acrosome.

9. The acrosome of the spermatozoon of Cavia is formed from the proacrosomic granules which are differentiated within the archoplasm during the later growth stages of the sperinatocyte.

10. The archoplasm in the sperniatocyte of Cavia is covered by the Golgi elements or dictyosomes, which in all probability are associated with the differentiation within the archoplasm of the proacrosomic granules.

11. Each of the spermatids derived from the spermatocyte contain an equal share of Golgi elements, archoplasm, and proacrosomic granules. According to Papanicolaou and Stockard the latter granules do not disintegrate during mitosis, but, keeping their individuality, become scattered in the cytoplasm, are subequally sorted out among the daughter cells, and eventually come to lie within the re-formed spermatid archoplasm.

12. Bach proacrosomic granule has a liquid-filled space formed around it, so that it comes to lie in an archoplasmic vacuole.

13. The several proacrosomic granules within their archo-plasmic vacuoles approach and fuse into fewer larger granulos, which eventually all come together to form a single largo granule lying in a single archoplasmic vacuole. This structure is known as the proacrosome.

14. The Golgi apparatus complex now consists of numbers of dictyosomes lying on the surface of the archoplasm : the latter contains near its centre the proacrosome. The latter soon becomes distinguishable into an inner darkly-staining bead surrounded by a paler cortical zone, the whole lying in the archoplasmic vacuole.

15. The Golgi apparatus complex has moved up towards the anterior end of the spermatid nucleus, and it now becomes applied to the nuclear membrane. Where the complex touches the membrane the Golgi elements or dictyosomes are pushed aside, so that the archoplasm comes into direct contact with the spermatid nuclear membrane.

16. From its more or less central position the proacrosome passes through the archoplasm and becomes applied to the nuclear membrane, upon which it becomes flattened so as to form a hemisphere. The proacrosome is now spoken of as the acrosome : it has an inner zone, an outer zone, and it is still covered on its outer side by the archoplasmic vacuole. Where the latter comes into contact Avith the archoplasm there is differentiated the covering membrane of the acrosome, which is rarely very clear.

17. The acrosome grows rapidly, and at a stage when it has differentiated to form a conspicuous cap at the anterior end of the sperinatid nucleus, the Golgi elements with archoplasmic remains, which hitherto covered and embraced the developing acrosome, gradually drift away and pass towards the posterior end of the spermatid.

18. The acrosome now develops by itself. The lower part of the archoplasmic vacuole spreads down past the equator of the spermatid nucleus, and the lower edges of the outer zone of the acrosome cover the equatorial region of the nucleus. The archoplasmic vacuole becomes less evident.

19. The outer zone of the acrosome grows very rapidly, becomes cone-shaped, and later flattened and crescentic in shape when the broad side of the sperm is examined. In the fully formed acrosome the outer zone of the acrosome is much greater in extent than the inner zone of the acrosome.