1818.] Sir Torbern Bergman. 3'23 



He examined the different species of hiradines, or leeches, 

 which are natives of Sweden. While engaged in this examina- 

 tion, he made a discovery which I shall endeavour to explain. 

 The females of the genus of insects, called by Linnaeus coccus, 

 adhere to the plants on which they feed so immoveably that 

 they have the appearance of galls rather than animals. Linnaeus, 

 in the Fauna Suecica, No. 2080, described an animalcule which 

 he was disposed to consider as a female coccus ; but as no one 

 had seen it, except adhering to aqueous plants, the Swedish 

 Pliny was unwilling to decide whether it was really a coccus or 

 the ovum of some aquatic animalcule. Berp-man instituted a 

 set of observations on this substance, and soon ascertained it to 

 be the ovum of the hirudo octoculata. Linnaeus was at first 

 unwilling to credit the truth of this discovery ; but when Berg- 

 man had convinced him of the accuracy of his observations by 

 ocular demonstration, Linnaeus sent the account of them, as 

 drawn up by his pupil, to the Stockholm Academy, with a very 

 flattering panegyric. Vidi et obstupui. 



Bergman speedily distinguished himself by numerous papers 

 on different branches of natural philosophy. He passed rapidly 

 through all the gradations of rank usually conferred on students 

 at Upsala, and in 1761 was appointed Magister Docens in 

 physics. During the six years which he filled this situation he 

 still further distinguished himself by a great number of ingenious 

 papers ; for example, on the aurora borealis, on the rainbow, on 

 the twilight, &c. 



In the year 1767, Johann Gottschalk Wallerius, who had 

 long been Professor of Chemistry at Upsala, and possessed a 

 very high reputation, resigned his chair. Bergman was at that 

 time by far the most distinguished young man at the University 

 of Upsala, and had not neglected his chemical more than his 

 mathematical studies. His dissertation on the manufacture of 

 alum, published on April 1, 1767, and his treatise on physical 

 geography, which had made its appearance a year earlier, afford 

 specimens of a minute knowledge both of chemistry and mine- 

 ralogy, such as could scarcely have been looked for from a 

 person who had not hitherto devoted himself exclusively to 

 chemical pursuits. He accordingly offered himself a candidate 

 for the vacant chair ; and his dissertation on the manufacture of 

 alum seems to have been composed chiefly to show his acquaint- 

 ance with the science which he aspired to teach. 



But Wallerius had other plans. There was a relation of his 

 own whom he wished to succeed him ; and such was the in- 

 fluence of that celebrated Professor, that there was every proba- 

 bility of his accomplishing his object. It is asserted by 

 Condorcet, that he attacked Bergman's dissertation on the 

 manufacture of alum in a style of acrimony which did him but 

 little credit. 



(iustavus IV. afterwards so distinguished when King of 



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