| Microcarriers materials may be composed by natural polymers and their derivative such as glutin, collagen, fibrin, chitin, dextran or cellulose. |
| When this is boiled with alcohol, the glutin above referred to is extracted, and vegetable fibrine is left. |
| By boiling with water, dilute acids or dilute alkalies, collagen is split up into gelatin or glutin. |
| Neither glutin nor chondrin occurs ready formed in the animal kingdom, but they separate when the tissues are boiled with water. |
