Other products were soluble in the ether-alcohol mixture: they were less highly nitrated, and constituted the so-called collodion guncotton.
A characteristic difference between guncotton and collodion cotton is the insolubility of the former in ether or alcohol or a mixture of these liquids.
The so-called collodion cottons are nitrated celluloses, but of a lower degree of nitration (as a rule) than guncotton.
But the wet collodion process was then the only one available, and its inconveniences were such as to preclude its extensive employment; the real triumphs of photographic astronomy began in 1875 with Huggins's adoption and adaptation of the gelatine dry plate.
P. 378), who used a collodion lens filled with carbonic acid.
Excited to emulation and employing the more rapid wet-collodion process, he succeeded before long in obtaining exquisitely defined lunar pictures, which remained unsurpassed until the appearance of the Rutherfurd photographs in 1865.
That such enzymes are formed in the protoplasm is evident from the behaviour of hyphae, which have been observed to pierce cell-membranes, the chitinous coats of insects, artificial collodion films and layers of wax, &c. That a fungus can secrete more than one enzyme, according to the materials its hyphae have to attack, has been shown by the extraction of diastase, inulase, trehalase, invertase, maltase, raffinase, malizitase, emulsin, trypsin and lipase from Aspergillus by Bourquelot, and similar events occur in other fungi.
The hyphae will also dissolve their way through a lamella of collodion, paraffin, parchment paper, elder-pith, or even cork or the wing of a fly, to do which it must excrete very different enzymes.
To remove these salicylic acid dissolved in flexible collodion is now generally employed.
Extract of belladonna is added to lessen the pain which might occur during the removal of the corn, and this acts as a corrective, while the flexible collodion forms a means of applying it conveniently, and constitutes the vehicle.