Cites J.N. Langley and H. Sewall, 'On the Changes in Pepsin-forming Glands During Secretion', Journal of Physiology 2 (4) (1879), pp. 281-322.
Description:

'Sewall and myself [note: 'Langley and Sewall, Proc. Roy. Soc., Oct., 1879, p. 383; Jour. of Physiol., vol. ii., p. 283, 879.'] found that the oesophageal gland-cells occasionally showed clumps of highly refractive granules in their peripheral portions. To distinguish these from the proper granules of the cells, we called them "border" granules. Further investigation has shown me that these are really fat globules. Their position is very constant and they give a striking appearance to osmic acid specimens. Quite similar fat globules are occasionally to be seen in the pancreatic gland-cells. They occur also in the gastric gland cells of the Frog, Toad, and Newt (see Plate 78, fig. 7), although their arrangement is not quite so regular. In a subsequent paper I hope to discuss the causes which influence the appearance of fat globules in the above and in other secretory gland-cells.' (665)

 

'It was stated by Sewall and myself [note: 'Op. cit., p. 283'] that absolute alcohol added to the fresh teased-out gland altered the normal appearances; and I have said above that the granules are in part dissolved. Nevertheless, alcohol specimens of oesophageal glands taken during digestion show the two zones in the gland-cells; the non-granular zone stains with carmine, and thus specimens can be obtained (Plate 77, fig. 8), which, except for the smaller size of the cells, closely resemble similarly prepared specimens of the pancreas. It is almost unnecessary to remark that the "granules" of the inner zone in alcohol specimens are not the granules present in the fresh gland. With Zeiss', oc. 2, obj. E or F, the granular zone appears as a fine network.' (670)

 

'The extent to which the disappearance of granules proceeds varies in different cases: in many cases two days after feeding [note: 'Nussbaum (op. cit., s. 749) made some observations upon the direct stimulation of the oesophageal mucous membrane, the cardia being ligatured before the animal was fed with sponge. He found under such circumstances that the granules entirely disappeared from the cells in three to five hours. Sewall and myself (op. cit., p. 285) were unable to observe any such rapid action.'] with a rather large piece of sponge, occasionally in a less time, scarcely any granules are left; and in some glands not a granule is to be seen (Plate 77, fig. 6 (a), 6 (b)).' (671)

 

'In the account of the changes in the oesophageal glands given by Sewall and myself there were two points which clashed with the earlier observations which Nussbaum made on osmic acid specimens. He described the gland-cells of the normal hungry Frog as having a large clear zone, and found that on feeding the animal the granules increased so that in three to five hours a clear zone was no longer to be seen.

Grutzner's [note: 'Grützner, Pflüger's Arch., Bd. xx. s. 395, 1879.'] results suggest an explanation of the divergence between the account of Nussbaum and that of Sewall and myself. He finds that in the normally hungry Frog the oesophageal glands are granular throughout and diminish in granularity during digestion; but finds also that if a Frog is kept longer than usual without food a clear zone is then formed in the oesophageal glands and that on feeding there is at first an increase of granules. Thus according to Grützner, Nussbaum's results would represent what occurs in a pathological and not what occurs in a normal condition,

During the last year and a half I have made a considerable number of observations with the view of determining the points at issue. As regards the state of the glands in the normal hungry Frog I have seen no reason to alter my first-formed opinion.

In some Frogs a large clear zone in the oesophageal glands does occur, namely, in those in which there are signs of general inflammation. In nearly all cases in which I have found a marked clear zone in the gland-cells of a hungry Frog, the animal had some mark or other of an ill state of health. I have frequently selected lively, active Frogs, and sluggish, unhealthy ones from a batch brought to the laboratory, and in a few days examined the oesophageal glands. The gland-cells in the former were granular throughout; those of the latter had almost always a clear zone.' (672)

Cites M. Nussbaum, 'Ueber den Bau und die Thätigkeit der Drüsen: Die Fermentbildung in den Drüsen', Archiv für mikroskopische Anatomie 13 (1) (1877), pp. 721-755.
Description:

'The oesophageal glands. - These glands have been described by Swiecicki, [note: 'Swiecicki, Pflüger's Archiv., Bd. xiii., s. 444, 1876'] Nussbaum, [note: 'Nussbaum, Max Schultze's Arch., Bd. xiii., 1877.'] and Partsch. [note: 'Partsch, Max Schultze's Arch. Bd. xiv. s. 179, 1877.'] The glands are of the complex tubular type; [note: 'I apply the term "simple tubular" to such glands as consist of one tube; when several tubes are given off by one duct, I call the glands "compound" tubular; when the tube or tubes arising from a duct divide, I call the gland a "complex" tubular gland. Klein describes the oesophageal glands as acinous glands (Stricker's 'Handbook,' vol. i., p. 538)']  amongst the proper secreting cells are mucous cells, these occur in smallest number in the final dilatations of the ducts. In the ducts ciliated cells are sometimes, though rarely, to be seen. The secretory cells are cylindrical or conical and are smaller than the gastric gland-cells. Nussbaum [note: 'Op. cit., s. 748.'] has shown that, they contain in the fresh state conspicuous granules; in a teased-out fresh preparation many of these granules are seen floating in the fluid: they are three to five times as large as the granules seen on teasing out similarly the gastric glands; they are even larger than the granules of the pancreas.' (664)

 

'On adding alcohol the granules sometimes run together before the partial solution takes place. Thus, in one instance, I watched three granules lying close together; first one ran into its neighbour, then this into the remaining granule, the whole forming one large granule; in it several brighter spots appeared; later, the greater part suddenly vanished leaving four or five rather bright particles arranged so as to produce the appearance of a fragment of a small-meshed network, I have little doubt that the apparent network seen in the cells in alcohol specimens has its origin from these residual particles.' [No explicit citation of Nussbaum here. cf. Langley's earlier criticism of Nussbaum's use of alcohol to fix specimens.]

 

'It was shown by Nussbaum [note: 'Op. cit.'] that the cesopha'eal gland granules are preserved by osmic acid. In treating glands with this reagent I usually use the following method. The tissue is placed in a 1 per cent. solution for twenty-four hours, removed to 50 per cent. alcohol for fifteen minutes and then transferred to 75 per cent. alcohol. Sections are cut on the following day. In sections so prepared the granules are stained not very deeply and have a yellow-brown tint. The sections as a whole are less stained than similarly prepared sections of the stomach. The tint of staining of the gastric gland granules tends to be brown-black rather than yellow-brown.' (665)

 

'The extent to which the disappearance of granules proceeds varies in different cases: in many cases two days after feeding [note: 'Nussbaum (op. cit., s. 749) made some observations upon the direct stimulation of the oesophageal mucous membrane, the cardia being ligatured before the animal was fed with sponge. He found under such circumstances that the granules entirely disappeared from the cells in three to five hours. Sewall and myself (op. cit., p. 285) were unable to observe any such rapid action.'] with a rather large piece of sponge, occasionally in a less time, scarcely any granules are left; and in some glands not a granule is to be seen (Plate 77, fig. 6 (a), 6 (b)).' (671)

 

'In the account of the changes in the oesophageal glands given by Sewall and myself there were two points which clashed with the earlier observations which Nussbaum made on osmic acid specimens. He described the gland-cells of the normal hungry Frog as having a large clear zone, and found that on feeding the animal the granules increased so that in three to five hours a clear zone was no longer to be seen.

Grutzner's [note: 'Grützner, Pflüger's Arch., Bd. xx. s. 395, 1879.'] results suggest an explanation of the divergence between the account of Nussbaum and that of Sewall and myself. He finds that in the normally hungry Frog the oesophageal glands are granular throughout and diminish in granularity during digestion; but finds also that if a Frog is kept longer than usual without food a clear zone is then formed in the oesophageal glands and that on feeding there is at first an increase of granules. Thus according to Grützner, Nussbaum's results would represent what occurs in a pathological and not what occurs in a normal condition,

During the last year and a half I have made a considerable number of observations with the view of determining the points at issue. As regards the state of the glands in the normal hungry Frog I have seen no reason to alter my first-formed opinion.

In some Frogs a large clear zone in the oesophageal glands does occur, namely, in those in which there are signs of general inflammation. In nearly all cases in which I have found a marked clear zone in the gland-cells of a hungry Frog, the animal had some mark or other of an ill state of health. I have frequently selected lively, active Frogs, and sluggish, unhealthy ones from a batch brought to the laboratory, and in a few days examined the oesophageal glands. The gland-cells in the former were granular throughout; those of the latter had almost always a clear zone.' (672)

 

'Swiecicki concluded from his observations that the oesophageal glands are at any rate the chief source of pepsin, and that the gastric glands produce little, perhaps indeed none. [note: 'He says: "Alle diese Thatsachen spreben hiernach dafür dass bei den Frischen die Pepsinbildung vorzugsweise, ja vielleicht nur allein in dem Oesophagus von statten geht, während der die Belegzellen führende Magen die Saüre bildet" (s. 452).']

Nussbaum suggested that the pepsin arose from the oesophageal gland granules. He found a correspondence between the number of granules in the gland-cells and the amount of ferment contained by the glands. Sewall and myself, whilst differing from Nussbaum as to the times of increase and decrease of granules, came nevertheless to the conclusion that the granules were connected with the formation of ferment. To this conclusion we came partly on general grounds, partly by comparing Grützner's results on the times of increase and decrease of pepsin with our own on the times of increase and decrease of granules.

... I think we can fairly conclude that the granules give rise to the ferment.' (678-679)

 

'In the cell-protoplasm there is during secretion an increase of substance capable of reducing osmic acid.

In all the cases investigated above we have seen that the protoplasm of the "quiescent" gland-cells stains very slightly with osmic acid, whilst the protoplasm of the active cells stains more or less deeply.

This is opposed to the observations of Nussbaum, but Nussbaum, I think, directed his attention so much to the granules contained by the cells that he overlooked the cell-protoplasm.

I have not been able to satisfy myself of the meaning of this increase in stainingpower of the protoplasm. Since the granules split up during activity, we might imagine that the cells do not at once cast out the whole of the substances formed, but retain a certain proportion, and that this diffused throughout the cell causes it to stain more than normally with osmic acid.

There is, however, another way of looking at the fact. Generally speaking, the formation of granules goes hand-in-hand with a diminution in the power of staining of the cell-substance. In the latter period of digestion, when the granules are increasing the cell-substance stains less and less with osmic acid. In Triton taeniatus during the rapid increase in the granules which takes place from the fourth to the eighth hour of digestion there is a rapid diminution in the staining power of the cell.

This would indicate that the protoplasm of the cells, in passing through those changes which result in the formation of granules, uses up the substance stainable with osmic acid. This substance might be either taken up by the cell during secretion to be further assimilated, or it might be an integral part of the cell-protoplasm.

The facts we have at present are, I think, insufficient to allow any satisfactory conlclusion to be drawn on this point; but whatever the cause of it may be, it is, I think, a very general phenomena of cells to stain more deeply with osmic acid during active secretion than duiing rest. I have on a former occasion [note: 'Proc. Royal Soc., vol. xxix., p. 377, 1879; Jour. of Physiol., vol. ii., p. 261, 1879.'] pointed out that this is the case in the parotid, sub-maxillary, lachrymal, and infra-orbital glands of the Rabbit.

In parotid and sub-maxillary glands the resting cells treated with osmic acid show lightly-stained cell-substance with darker-stained granules; when the cells are similarly treated after a period of secretion the cell-substance is distinctly more deeply stained, the depth of staining increasing within certain limits with the length of time during which the cells have secreted.

In the lachrymal and infra-orbital glands the resting cells treated with osmic acid show a networked appearance, from the presence of a lightly-stained protoplasmic with a darker interprotoplasmic portion. When the cells are similarly treated after a period of secretion the networked appearance disappears from the outer portion of the cells; it now is homogeneous - the protoplasm stains deeper than before. After prolonged secretion the cells stain equal and fairly darkly throughout.

In all these glands, however, the increase of substance in the cell-protoplasm capable of staining with osmic acid, although distinct, is not so marked as it is in the gastric glands. Grützner [note: 'Grützner, Pflüger's Arch., Bd. xx., s. 399, 1879.'] has independently come to a somewhat similar conclusion. He found in all the salivary and gastric glands investigated by him a difference of tint in osmic acid specimens of the resting and of the active glands. The former he found to be grey-green, the latter a dirty (schmutzig) brown. This, indeed, represents not unfairly the general difference in tint of the glands in the respective states when examined with not too high a power. I should prefer to call the tint of the one yellow-brown and that of the other brown-black. Grützner applied his description to the cells as a whole; the yellow-brown tint is, however, in the main due to the staining of the cell-granules, the brown-black tint in the main to the staining of the cell-protoplasm.' (707)