On the nature of the substance found in the amyloid degeneration of various organs of the human body / by Francis Harris.

  • Harris, Francis.
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: On the nature of the substance found in the amyloid degeneration of various organs of the human body / by Francis Harris. Source: Wellcome Collection.

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    Dried tuiiicine was mixed with cold concentrated sulphuric acid. By degrees it dissolved without becoming coloured. The fluid was then poured, drop by drop, into a hundred times its weight of boiling water. The mixture was then kept boiling for an hour. It was then saturated with chalk, and, after having been filtered, was evaporated to a syrupy consistence. This syrupy fluid was a mixture of sugar with some substance of an indeterminate nature. It reduced energetically the potassio-tartrate of copper, and assumed a dark brown colour when boiled with caustic potash. To a mixture of this syrup with water, yeast was added, and fermentation was readily set up, with the production of carbonic acid and alcohol. The conversion of this substance into sugar was therefore fully The other substance, chitine, is the organic basis of the external skeleton of Crustacea arachnida, insecta, &c. It may be obtained by a method similar to that employed for the prepara¬ tion of tunicine. As early as 1823, M. Odier* considered it to be a substance approaching in its nature to cellulose. It differs from tunicine in one very important particular—it has not yet been obtained free from nitrogen. M. Berthelot states that he boiled the chitine, which he obtained from the shells of lobsters, for several weeks with dilute sulphuric acid; and that the mixture was then left for a period of fourteen months at the ordinary temperature of the air, but that after this time the chitine was found almost intact, and still contained 5 to 7 per cent, of nitrogen. Various other analyses of it have been made at different times. In one by Messrs. Children and Daniellf its composition is stated to be Carbon . • • . 46.08 Hydrogen « • . 5.96 Nitrogen • • . 10.29 Oxygen . Schmidt found it to contain j . 37.41 Carbon . • • . 46.69 Hydrogen • • 6.69 Nitrogen • • 6.33 but found in it no trace of phosphorus or sulphur. Memuires de la Suciele d'Histoire Nat. de JPatdSf Tome I. p. 29. 1823. + Todd’s Cyclop, of An at. Vol. II. p. 882. I Zur vergleich. Physiologic der Wirhellosen^ p. 39. 1845.