1. Observations on the living ovary.
The earthworm ovary, as also that of the medicinal leech, is surprisingly favourable material for the study of the Golgi apparatus and the mitochondria in the living condition. The Golgi elements stand out very prominently in all stages of oogenesis as highly refractile spherules of a dark-greyish colour, performing a dancing movement in the cell. In the earliest oogonia situated near the septal insertion of the ovary there is a single Golgi spherule lying near the nuclear membrane. It probably divides at first into two and then into four, till in advanced oocytes there is a large number of Golgi elements distributed uniformly in the cytoplasm. The mitochondria in the earliest oogonia cannot be detected. Soon, however, they arise in the form of either a horseshoe closely fitting the nuclear membrane or a roundish mass, consisting of whitish granules, much less refractile than the Golgi elements. Gradually they spread out in the cytoplasm and perform a dancing movement. The Golgi elements and the mitochondria remain unaltered for a long time after the death of the cell.
Attention is drawn to the excellent work of Foot and Strobell (1901), who described in the fresh egg of Allolobophora only two types of granules, namely, the ‘deutoplasmic’ or ‘osmiophile’ granules (Golgi elements) and the ‘archoplasmic’ or ‘yolk-nucleus’ granules (mitochondria). They have also shown only one osmiophile granule in their photographs of the earliest oogonia.
2. Observations on the living stained ovary.
Neutral red and janus green B do not in any way improve the visibility of the inclusions, if indeed any improvement were desired. The Golgi elements do not at all stain with neutral red. The mitochondria may appear slightly blue with janus green.
3. Observations on fresh ovaries treated with osmic acid.
The importance of this technique is greatly emphasized. After five to ten minutes' osmication the Golgi elements become copper-coloured, but they still appear solid. After half an hour's osmication they become slightly black and each element now shows very clearly a dark peripheral rim and a clear central area. The element is therefore not a solid or a semi-solid body, but a vesicle with a definite osmiophilic rim and a hollow interior. After two hours' osmication the vesicles become still blacker.
4. Experiments with the Centrifuge.
The centrifuge very clearly reveals the existence of only two types of inclusions, namely, the Golgi elements and the mitochondria. There is neither yolk nor any other type of inclusion.
5. Observations on Fixed Preparations.
If a Champy-fixed ovary is mounted whole, the Golgi elements appear as black granules. Within a month or so, however, they are decolorized by xylol. This proves the existence of fat inside the Golgi vesicle. In Champy-fixed sections, however, the vesicles are decolorized immediately after immersion in xylol. Kolatschev preparations demonstrate very satisfactorily the vesicular shape of the Golgi element.
6. The morphology of the Golgi apparatus in general is discussed in detail in the light of the recent work of Gatenby, Hirschler, Bowen, and others.