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:

'Early in the past year (1877), I commenced to make some experiments to test the conclusions arrived at by Nussbaum [note: ' "Die Fermentbildung in den Druisen," Archiv für microsc. Anat. XIII. (1876 [sic]), p. 721.'], concerning the recognition under the microscope of the amylolytic ferment of the salivary glands. Circumstances prevented me from carrying them out as I had purposed, and in the meanwhile, Grützner [note: 'Pflüger's Archiv, xvi. (1877), p. 105'] has been working at the subject, and arrived at results which invalidate Nussbaum's conclusions. Incomplete as my experiments are, still they may serve to fill up, to a certain extent, a gap in Grützner's observations so far as the sub-maxillary gland of the rabbit is concerned.

The starting-point of Nussbaum's work was the fact that the amylolytic ferment as prepared by von Wittich's method, reduced osmic acid; from this he argued that those parts of a gland wlhich contain ferment, must be stained black by this reagent, and that if the ferment be extracted from the gland before the latter is treated with osmic acid, the parts which are no longer deeply stained must represent the parts which are concerned in ferment-production. His method of preparation in order to observe the difference of colouration before and after the removal of the ferment, is the following: he places one piece of the gland warm from the body, in a 1 per cent. aqueous solution of osmic acid for a definite time, and another piece in osmic acid of a like strength for a like time, after it has been extracted with glycerine for two or three days, with or without previous hardening in alcohol. Treating in this way the sub-maxillary gland of the rabbit, he obtained from the piece of the gland laid fresh in osmic acid, certain cells of the alveoli, very deeply stained; these were the more centrally lying cells coming immediately after the ductules [note: 'I use the word ductules for those small terminal ducts which have lost the characteristic appearance of the larger ducts, in no longer possessing a cylindrical epithelium with a striated outer border; they were called by their discoverer, Ebner, " Schaltstücke."'], which for convenience, and for reasons to be given presently, I will call "transition" cells; in the piece however that had been treated with glycerine for the extraction of ferment, he found the transition-cells to be stained not more deeply than those in the peripheral parts of the alveoli. He concludes then from this, that the amylolytic ferment is formed in the transition-cells; the more peripheral alveolar cells not being concerned in ferment-production.

Leaving for the moment the consideration as to whether this deduction is logical or no, I would first discuss the facts on which the deduction is founded.

The appearances described by Nussbaum after the gland has been treated in the above-mentioned ways, do not, I think, represent the actual state of things.' (68-69)

Cites Plate II, Journal of Physiology 1 (1) (1878). Figs. 1-3 from J.N. Langley, 'Some Remarks on the Formation of Ferment' and fig. 4 from W. Stirling, 'On Hyperplasia of the Muscular Tissue'.
Description:

Fig. 4 in text:

'It appears to me, on the contrary [to the assertion of Nussbaum], that the cells composing the ductule [of the sub-maxillary gland of the Rabbit] are but slightly elongated or not at all, and graduate as regards size and appearance into the alveolar cells, so that of particular ones it is difficult to say whether they belong to the ductule, or to the alveolus; hence I name them transition cells. A favourable example of this transition is drawn in Pl. II., Fig. 4. This is taken from the sub-maxillary gland of a rabbit which had been treated with osmic acid, 1 per cent., for two hours; (a) ductule, (b) transition-cells, (c) alveolar cells proper. This offers an approximate explanation of the colouration by osmic acid of the transition-cells observed by Nussbaum, viz., that they are as much allied to the duct-cells as to the alveolar cells, and preserve the property of the duct-cells to readily reduce osmic acid.' (69)

Cited by J.N. Langley, 'On the Changes in Serous Glands during Secretion', Journal of Physiology 2 (4) (1879), pp. 261-322.
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'In a previous paper [note: 'Journal of Physiology, Vol. I. p. 69, 1878. At that time I could not obtain any appreciable amount of ferment from the sub-maxillary gland of the rabbit; since I have made no further experiments in that direction, I treat the subject here purely from a histological standpoint.'] I contested the justice of Nussbaum's conclusion that ferment is formed in, and only in, transition-cells. I there pointed out that after two hours osmic acid the ducts stain darkest, and the ductules equally with the transition-cells; consequently there is no reason for limiting the ferment to the transition-cells if we are to judge of the presence of ferment by the depth of staining with osmic acid.' (271)

'I have said, in an earlier paper [note: 'Op. cit. p. 70.'], that if the gland be treated with absolute alcohol before osmic acid, the deep staining is absent from every part of the gland, the transition-cells included; and that consequently it is very improbable that the staining substance could be, in any case, ferment. Nussbaum [note: 'Arch. f. Mik. Anat., Bd. xvi. s. 543, 1879.'] obtains a different result. As however I always obtain the transition-cells of only a light yellow colour, when absolute alcohol is used before osmic acid, I can but repeat my original statement, and leave the matter to other observers to decide. ' (272)

Cited by M. Nussbaum, 'Ueber den Bau und die Thätigkeit der Drüsen. III. Mittheilung. Die Permentbildung in den Drüsen', Archiv für mikroskopische Anatomie 16 (1) (1879), pp. 532-544.
Description:

'In meiner ersten Mittheilung über die Fermentbildung in den Drüsen hatte ich unter Anderem auch von der Glandula submaxillaris des Kaninchens gehandelt. Kurz nachdem ich die zweite Mittheilung über diesen Gegenstand veröffentlicht hatte, trat Herr Langley in Kühne's Untersuchungen mit der Beobachtung mir entgegen, dass durch Alcohol die von mir als Ferment angesprochene Substanz zu extrahiren sei, dass also diese Substanz, die sich allerdings in Ueberosmiumsäure färbe, kein Ferment sei. In der Glandula submaxillaris des Kaninchens findet sich aber dennoch Ferment; von der Submaxillardrüse des Rindes, die ebenfalls kein Ferment enthalten soll, habe ich im XV. Bde. d. Arch. quantitative Bestimmungen von Zucker mitgetheilt, der nach Zusatz geeigneter Extracte der vermeintlich fermentfreien Drüsensubstanz zu Kleister gebildet worden war. Für die Glandula submaxillaris des Kaninchens behaupte ich auch heute in Grundlage meiner früheren und inzwischen recht oft erneuerten Versuche ein nachweisbares Vorkommen von Ferment, wenn man die Drüse sofort vom mitten in der Nahrungsaufnahme getödteten Thiere entnimmt.

Langley hat übrigens nicht das gesehen, was ich beschrieben und abgebildet habe. Nicht die Drüsengangzellen, wie Langley meint, sondern die Uebergangszellen werden in fermenthaltigen Drüsen durch Ueberosmiumsäure am intensivsten geschwärzt. So mag es auch kommen, dass Langley eine Substanz durch Alcohol extrahirt zu haben glaubt, die auch vor der Alcoholbehandlung von zweifelhaftem Character war. In fermenthaltigen Drüsen wird durch voraufgehende Erhärtung in Alcohol die durch Ueberosmiumsäure zu bewirkende Färbung der Zellen am Uebergang der Alveolen in den Ausführungsgang nicht aufgehoben. Man muss nur dafür sorgen, dass das in Alcohol gehärtete und dadurch specifisch Ieichtere Drüsenstückchen mit der Ueberosmiumsäure gehörig in Contact kommt. Berücksichtigt man nun ferner, dass selbst bei frischen Geweben die Einwirkung der Ueberosmiumsäure wegen der stattfindenden Erhärtung nur eine oberflächliche ist und nicht in die Tiefe dringt, so wird man die zu untersuchenden Parthien an Präparaten, die schon vor der Einbringung in Ueberosmiumsäure stark gehärtet waren, nur an der Oberfläche suchen. Wenn nun auch in Folge der Erhärtung die Osmiumwirkung an Aleoholpräparaten im Allgemeinen eine geringere ist als bei frischen Drüsen, so liegt das beste Argument gegen Langley's Raisonnemerit -- der in Ueberosmiumsäure sich schwärzende Stoff sei dem Gewebe durch absoluten Alcohol zu entziehen -- in der von mir d. Archiv Bd. XIII gemachten Angabe, dass die nach mehrfacher Fällung mit Alcohol gewonnenen Drüsenextracte sich in Ueberosmiumsäure sehwärzen.' (543-544)