reached his seventeenth year. He then went to Berlin, and entered the military school of medicine known as the Frederick William Institute, or as the Pépinière. It is true that, if medicine was the study of his choice, there were ample facilities for it at any German university. But there were reasons which rendered it advisable to send him to a military institution. Prussia demands of all her sons several years of active service in the army, to begin when they are twenty-one years of age. This regulation provides her with large available forces, but sadly interferes with the pursuits of the young men at a time when the foundation must be laid for their future career. To overcome this difficulty, and to create at the same time a comparatively cultured army, it is provided that those who attend for a short period some military institution, and pass a satisfactory examination of a certain literary grade, shall be more or less exempt from active service in time of peace. Young Helmholtz's parents considered it best that he should avail himself of this provision at an early age, in order to insure for him an uninterrupted season of study in subsequent years. But Hermann had also his own reason for entering the military school of medicine. He had been seized with that martial fever which is apt to attack the youth of countries where there is continually a gaudy display of soldiers.
He went to Berlin, and on the three years which he spent there Helmholtz still looks back as the most pleasant of his life. There were strict rules to be obeyed, and there was hard study to be done; but there were also short furloughs to be obtained for rambles through the city, and some even long enough for a journey to the old home at Potsdam. The constant feeling of being on duty developed in him that noble manliness which so deeply marks every feature of his face.
When he was twenty, he graduated from the Pépinière with an article prepared for his examination marked with all the learning that he has since made his own. His dissertation was on the subject of the nervous system of invertebrate animals, and is the only morphological investigation which he has ever made.
His treatise evinced such uncommon ability that he was at once ordered to attend as assistant surgeon the hospital of the Charité, in Berlin, and after a few months he was promoted to the rank of physician in a regiment of hussars, stationed at Potsdam. This was wise, as it placed the youth again under the wholesome restraints and the kindly influences of the family circle, instead of allowing his hard-earned knowledge and well-trained physique to run to waste, like those of most young officers.
Helmholtz published in the same year the first fruit of his independent researches. It was an article on the nature of fermentation, which contains several remarkable suggestions on the subject of spontaneous generation. The excellence of this production opened to him the pages of the prominent medical magazines, and gave him the
