22 THE LARCH CANKER 



disease. Willkomm described the formation of a canker -in 

 great detail, and even grew cultures of the fungus and 

 observed the germination of the spores. But he assumed, 

 without experimental evidence, that spores of the fungus 

 could germinate on larch stems and could give rise to 

 cankers by piercing the unwounded bark with their germ 

 tubes, a supposition which was subsequently shown by 

 Hartig to be inaccurate. Also he never proved that the 

 disease could be caused by the fungus acting alone, or 

 indeed that the fungus was a cause at all. All he showed 

 was that in every canker he examined mycelium, and 

 generally apothecia, were present ; but whether the fungus 

 caused the disease or the diseased spots formed a suitable 

 breeding-ground for the fungus was left undecided. Patho- 

 logy, as we know it, was not then born. 



Thirteen years later, Robert Hartig l (1880), after working 

 out numerous other tree-diseases, published his paper on 

 larch canker, which has remained since then as the standard 

 account of the disease. He states that the first complaints 

 of the disease were made in Germany about 1850, and by 

 1870 it had become a source of danger throughout the 

 whole of Germany and Scotland. It was especially pre- 

 valent in damp and foggy regions, and he thought it was 

 largely encouraged by inhibition of transpiration. It 

 occurred, however, in the Tyrol up to nearly 2,OOQ m., and 

 in that region cankers nearly one hundred years old were 



1 Robert Hartig was born May 30, 1839, at Brunswick. Both his father 

 and grandfather were distinguished foresters, and he had an early training 

 in scientific forestry, both under his father at Brunswick (1861-3) and at 

 Berlin (1863-4). He served his time in the forests, and after taking 'his 

 doctor's degree at the university of Marburg he filled various positions in 

 the. forest service. In 1869 he was appointed professor of botany at 

 Eberswalde, and from here published some of his most important patho- 

 logical papers, including ' Wichtige Krankheiten der Waldbaume' (1874) 

 and the ' Zersetzungserscheinungen ' (1878). In 1878 he was elected to 

 the new chair of forest botany at Munich, and remained there till his death 

 in 1901. His extraordinary energy is shown by the number and impor- 

 tance of his published works, which comprised 16 books and 130 other 

 papers (vide Biographisches Jahrbuch it. Deutscher Nekrolog, Bd. vi, S. 93, 

 and Zentralblatt fur das gesatnte Farstwesen, 1902, pp. 37-46). 



