Page:The Harveian oration 1905.djvu/100

 parations of certain organs or their active principles, either internally or hypodermically, or even by their local use. Whether these results can be explained by the doctrine of "internal secretions" or in some other way, there can be no doubt as to their reality, and agents of this nature are now definitely available for therapeutic purposes. It will suffice to mention supra-renal extract and adrenalin as prominent examples, which, as you are aware, are now so extensively used in medical and surgical practice.

Taking a glance into the future, it appears to me that there is no necessary or obvious limit to the discovery of additional therapeutic agents, which may be advantageously employed for their direct effects upon the heart or vessels, whether derived from the inorganic, the vegetable, or the animal kingdom, or prepared in the chemical laboratory. Further researches in this direction are deserving of every possible encouragement, as being likely to lead to most valuable results, if carried out systematically and judiciously.

2. Among the most popular, or I might say even fashionable methods of treatment employed in relation to the circulatory system at the present day, are those which may be described as physical, balneological, or a combination of both. They chiefly include massage, either general, or local over the præcordial region; graduated and progressive walking exercise, as practised in the "mountain-cure"; carefully conducted gymnastic exercises of