Old theories, and old men who cling to them, must take themselves out of the way as the new generation with its fresh thoughts and altered habits of mind comes forward to take the place of that which is dying out.  This was a truth which the fiery old theorist found it very hard to learn, and harder to bear, as it was forced upon him.  For the hour of his lecture was succeeded by that of a younger and far more popular professor.  As his lecture drew towards its close, the benches, thinly sprinkled with students, began to fill up; the doors creaked open and banged back oftener and oftener, until at last the sound grew almost continuous, and the voice of the lecturer became a leonine growl as he strove in vain to be heard over the noise of doors and footsteps.

Broussais was now sixty-two years old.  The new generation had outgrown his doctrines, and the Professor for whose hour the benches had filled themselves belonged to that new generation.  Gabriel Andral was little more than half the age of Broussais, in the full prime and vigor of manhood at thirty-seven years.  He was a rapid, fluent, fervid, and imaginative speaker, pleasing in aspect and manner,—­a strong contrast to the harsh, vituperative old man who had just preceded him.  His Clinique Medicale is still valuable as a collection of cases, and his researches on the blood, conducted in association with Gavarret, contributed new and valuable facts to science.  But I remember him chiefly as one of those instructors whose natural eloquence made it delightful to listen to him.  I doubt if I or my fellow-students did full justice either to him or to the famous physician of Hotel Dieu, Chomel.  We had addicted ourselves almost too closely to the words of another master, by whom we were ready to swear as against all teachers that ever were or ever would be.

This object of our reverence, I might almost say idolatry, was one whose name is well known to most of the young men before me, even to those who may know comparatively little of his works and teachings.  Pierre Charles Alexandre Louis, at the age of forty-seven, as I recall him, was a tall, rather spare, dignified personage, of serene and grave aspect, but with a pleasant smile and kindly voice for the student with whom he came into personal relations.  If I summed up the lessons of Louis in two expressions, they would be these; I do not hold him answerable for the words, but I will condense them after my own fashion in French, and then give them to you, expanded somewhat, in English: 

     Formez toujours des idees nettes. 
     Fuyez toujours les a peu pres.

Always make sure that you form a distinct and clear idea of the matter you are considering.

Always avoid vague approximations where exact estimates are possible; about so many,—­about so much, instead of the precise number and quantity.