At the Lister Institute of Preventive Medicine, liquid air has been brought into use as an agent in biological research.
An inquiry into the intracellular constituents of the typhoid bacillus, initiated under the direction of Doctor Allan Macfadyen, necessitated the separation of the cell-plasma of the organism.
The method at first adopted for the disintegration of the bacteria was to mix them with silver-sand and churn the whole up in a closed vessel in which a series of horizontal vanes revolved at a high speed.
But certain disadvantages attached to this procedure, and accordingly some means was sought to do away with the sand and triturate the bacilli per se.
This was found in liquid air, which, as had long before been shown at the Royal Institution, has the power of reducing materials like grass or the leaves of plants to such a state of brittleness that they can easily be powdered in a mortar.