his vitalistic hypothesis did not prevent him in the least from directing his labor to establish life phenomena on a physico-chemical basis. Even the vitalistic principle, as it appertains to the philosophy of the present day, is largely a matter of man's personal and ultimate view of his own life and his own destiny.
In our consideration of the relation of Müller's thought to the Naturphilosophie of his time, we must not deny the fact that Müller did recognize a grain of truth in the general philosophic tendencies of that day. As Verworn says: "While keeping constantly in mind the large problems and the goal of science, he regarded critically the special methods and questions only as means to an end—as means for arriving at a harmonious conception of nature." Throughout his whole life he remained steadfastly true to this philosophical conception of science which he had set forth in his inaugural address, "Concerning the Need of Physiology for a Philosophic Consideration of Nature." Verworn further laments that modern science has now so largely lost this element of philosophy, which it had gained as a result of Müller's treatment.
Having dealt thus far with the more abstract phase of Müller's activity and thought, let us now consider more concretely, for a few moments, first the extent of the realm over which Müller exercised so marvelous a command.
When we examine the list of 260 and more complete publications which have come from Müller's pen, we are better able to comprehend the universality of his activities; and it must be understood in this connection that in this great number there are few which represent merely a superficial dalliance with a possible line of investigation. They demonstrate, in almost every case, that Müller plunged boldly into the very heart of the matter which at the time received his fullest consideration. The main subjects to which his contributions appertain, include the following:
| 1. | The Physiology of Motion. |
| 2. | The Life of the Fœtus |
| 3. | The Sense Organs. |
| 4. | Dissection of Invertebrates; also |
| (a) their development | |
| (b) the histology of their tissues. | |
| 5. | Nerve Physiology. |
| 6. | Animal Chemistry. |
| 7. | Human Anatomy. |
| 8. | Ethnography. |
| 9. | Comparative Anatomy of Vertebrates. |
| 10. | Physiology of the Voice and Speech. |
| 11. | Pathological Anatomy. |
| 12. | Systematic Zoology. |
| 13. | Paleontology. |
It is clear that such an extent and variety of undertakings could not result from a single line of investigation, but required a universal activity which it is safe to say has never been equaled by any investi-
