It has been stated on high authority that domestic pets such as parrots may contract consumption from their masters, and that no less than thirty-six per cent. of these birds brought to the veterinary college in Berlin are found to be suffering from tuberculosis. In that much-dreaded South African cattle disease, rinderpest, the infection, contrary to what is found in the case of tuberculous animals, is principally spread by the _materies morbi_ being liberated in the air expired by afflicted cattle, the contagious area surrounding an infected animal extending to as much as a hundred yards and more. Again, as regards pleuro-pneumonia in cattle, the contagion is given off in the air expired, and owing to the length of time which elapses before the lung becomes completely healed and healthy, even after a period of from six to nine months, the expired air may still prove a source of infection. In an official report on the open-air treatment of consumption in Germany a case is mentioned in which the patient, a farmer by occupation, had contracted the disease from some tuberculous cattle which he had on his farm. The writer goes on to say, "This case is worthy of special attention, inasmuch as it indicates that in addition to the danger of contracting the disease from the use of milk or meat derived from tuberculous animals, the tending of such animals may serve to convey the infection to man possibly much more frequently than has hitherto been supposed." In addition to the above instances of the responsible part played by air in the dissemination of consumption many others might be cited, but perhaps the most striking is that in which a scientific assistant of Tappeiner contracted the disease, and succumbed to it, in the course of some experiments which were being made to ascertain whether consumption could be communicated to animals by spraying them with an emulsion of the sputum of consumptive patients.