This one class of cases was brought fortuitously under the observation of Dr. Holland, and he has done what a competent officer of health could scarcely have omitted to attempt to do,—to devise means of prevention and reclaim their execution. One benevolent inventor proposed the adoption of a magnetic guard, or mouth-piece, the efficiency of which consisted in the attraction of the metallic particles evolved in the process of grinding. But the dust to which the grinder was exposed consisted of the gritty particles of the stone as well as of the metallic particles of the instruments ground, and if the invention had been adopted, it would still have left the men exposed to the gritty particles. It was not, however, adopted, nor does it appear that any efficient preventive would be voluntarily adopted by these reckless men. Dr. Holland invented another mode, which acts independently of the men, and which is very simple, and, it is confidently stated, that after a trial of some years, it has proved equal to the complete correction of the evil. It consists of an arrangement by which a current of air, directed over the work, carries from the workman clear out of the apartment all the gritty as well as all the metallic particles. The expense of the apparatus would scarcely exceed the proportion of a sovereign to each grinder. But it is not adopted; and Dr. Holland is in the position of an officer of health, on behalf of mothers and children, to reclaim authoritative intervention and the interests of society to arrest the suicidal and demoralizing waste of life. Having consulted his experience on the advantages of such an office as that in question to the working classes, he speaks in strong and confident terms of the benefits to be derived from it:—