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 + (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 régions, and he thought it was 
largely encouraged by inhibition of transpiration. It 
occurred, however, in the Tyrol up to nearly 2,000 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 Waldbiume’ (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 u. Deutscher Nekrolog, Bd. vi, 8. 93, 
and Zentralblatt fiir das gesamte Forstwesen, 1902, pp. 37-46). 
