Text-book of histology : including the microscopic technic / by Philipp Stöhr ; translated from the tenth German edition by Emma L. Bilstein ; edited, with additions by Alfred Schaper.

  • Philipp Stöhr
Date:
1904
Catalogue details

Licence: In copyright

Credit: Text-book of histology : including the microscopic technic / by Philipp Stöhr ; translated from the tenth German edition by Emma L. Bilstein ; edited, with additions by Alfred Schaper. Source: Wellcome Collection.

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    Weaker alcohol, for example, 90 per cent. alcohol, acts very dif- ferently, it shrivels tlie object and therefore cannot be used instead of 95 per cent. alcohol. 2. Chromic acid is mainly used in two aqueous Solutions : (a) As a o. 1 or a o. 5 per cent. solution (p. 21), which is especially suitable for organs that contain much loose connective tissue. This strong solution imparts a superior consistence to connective tissue, but has the disadvantage of making the staining difficult; it is also suitable for the fixation of karyokinetic figures. The objects remain in the chro- mic-acid solution for from one to eight days, are then washed in running water for from tliree to four hours or, if this is not possible, placedforthe same length of time in water renewed three or four times, then trans- ferred to distilled water for a few minutes, and finally hardened in alco- hol of gradually increased strength (§ 5) and protected from daylight (p. 35, remark *). (b) As a 0.05 per cent. solution, which may be prepared by dilut- ing the 0.1 per cent. solution with an equal volume of distilled water. The application is the same as that of solution a, except that the objects remain only twenty-four hours in solution b. Chromic acid Solutions penetrate slowly ; accordingly, if the tissue is submitted to the action of the medium for so brief a period as twenty- four hours, only small pieces, 5 to 10 mm. in diameter, should be pre- served. 3. Nitric acid in a 3 per cent. solution (3 c.c. of concentrated nitric acid [p. 20] to 97 c.c. of distilled water), like the strong chromic acid solution, is an admirable medium for organs rieh in connective tissue. The objects remain for from five to eight hours in this solution and with- out the previous use of water are transferred directly into alcohol of gradually increased strength for hardening (§ 5). 4. Formaldehyde, in from 8 to 10 per cent. solution (prepared by diluting 20 c.c. of commercial formol [p. 21] with 80 c.c. of distilled water) is a good medium for the fixation of cell structures; it acts similarly to osmium Solutions.* The objects should remain 48 hours or more in the formaldehyde solution and are then at once trans- ferred to absolute alcohol, in which they are hardened for at least two days. 5. Potassium-bichromate-acetic acid (p. 21).—Place the objects in the liquid and after from 18 to 24 hours wash them for about three hours in (if possible running) water and then harden in gradually strengthened * Cf. also the Substitution of the osmic acid in the Golgi mixture.
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