1/6 THE HISTORY OF BIOLOGY 



discover a treatment that may assist the working of nature. What he really 

 means when he talks of "nature" is not at all clear — whether it is a com- 

 bination of the individual's life-manifestations or some special life-force; 

 similarly, one does not gain a very clear explanation of the ideas he borrowed 

 from Hippocrates concerning the fluids of the body and the balance or dis- 

 turbances therein. His general conception of nature is on the whole purely 

 empirical — in this he was influenced by Bacon, whom, indeed, he quotes 

 with admiration. In certain cases, it is true, he can form quite daring hy- 

 potheses, but as a rule he consistently applies his principle as to observa- 

 tion's being the only source of knowledge in disease.^ This principle has 

 indeed been adopted by posterity, but he also exercised a powerful influence 

 on the medical and biological thinkers of the immediately succeeding age, 

 although these latter could not restrain themselves within the limits which 

 he laid down for research, but went further afield in the world of 

 hypothesis. 



Among these medical researchers who formed general theories of impor- 

 tance to the development of biology, two men are conspicuous at the begin- 

 ning of the eighteenth century who, born in the same year and working in 

 the same town, yet proved in all essentials strangely contrasted. These two 

 were Hoffmann and Stahl. 



Friedrich Hoffmann was born in Halle in 1660, the son of a wealthy 

 physician. At the age of fifteen he had the misfortune to lose both his parents, 

 who died of the plague, as well as his inheritance, as a result of a fire, and 

 thus early had to fend for himself. He was given an opportunity, however, 

 of studying medicine at the University of Jena, where a highly reputed 

 representative of the chemical and medical research of the period, G. W. 

 Wedel, was his teacher. Having further studied at Erfurt, he took his de- 

 gree at Jena, spent some time in England, where he made the acquaintance 

 of Boyle, and then set up as a practitioner in a couple of small German states 

 until, in 1693, he was called to an appointment at the newly founded uni- 

 versity in his native town of Halle. There he spent the rest of his life as a 

 professor, with the exception of a couple of years which he spent at the court 

 in Berlin. His work both as a teacher and as a physician was crowned with 

 extraordinary success: among his numerous pupils were included even old 

 doctors who sought to complete their training with him; is a practitioner 

 he was resorted to by high and low and was overwhelmed with consulta- 

 tions and loaded with brilliant honours. Considerate even towards those of 

 different opinion, of an affectionate, sympathetic nature, he was himself 

 universally beloved. He died in 1741, in harness to the last. 



^ In his own circle his contempt for theories seems sometimes to have been expressed in 

 a somewhat original way ; thus, a colleague who asked for advice regarding the choice of medical 

 literature was told to read Don Quixete. 



