Methods of staining the nervous system / by Bernhard Pollack ; translated from the 2nd German ed. by William R. Jack.

  • Pollack, B. (Bernhard)
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Methods of staining the nervous system / by Bernhard Pollack ; translated from the 2nd German ed. by William R. Jack. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    108/164 (page 92)
    2. It is impregnated for twenty-four hours in a 1 per cent, solution of silver nitrate. 3. It is again laid for from twenty-four to thirty-six hours in ;a weaker solution of osmic acid and bichromate (1 per cent, •osmic acid, 1,0; 2-5 per cent, bichromate of potash, 10,0). 4. It is once more treated for twenty-four hours with the silver solution. The process may sometimes be advantageously repeated a second time, thus making a triple out of the double method. As the result of his researches, Kallius ^ considers it important for the success of the impregnation that the time diiring which the mixture of Golgi and Cajal is used should be carefully observed. He took retinse in as fresh a state as possible, and allowed them to remain in the fluid for from twelve to seventy-two hours. In this way he often found that ■only cells of a special kind were stained. For example, after twelve hours it was frequently only the rods and cones and a few bipolar cells that were impregnated; after twelve hours other bipolar cells and the so-called spongioblasts. Then followed the ganglion cells of the optic nerve, later the nerve- fibres, and, when the ganglionic elements no longer stained well, the supporting cells were brought into view. In opposition to van Gehuchten, he considered that it was not necessary to leave the retina for more than twenty-four hours in the solution of silver nitrate, but he thought it often advantageous to substitute bichromate of soda or ammonia for the bichromate of potash. To obviate the precipitation of bichromate of silver, he covered the surface of the retina facing the vitreous humour with as thin as possible a layer of gelatine before placing it in the silver solution. He rejects Cajal's method of rolling up the retina, because it cannot afterwards be flattened out, and it is therefore impossible to prepare and examine a series of horizontal sections through its whole thickness, 1 Kallius : Untersuchungen liber die Netzhaut der Saugethiere. Merkel-Bonnet ii*., 1894.