86 HEART-ROT 
Historical. The history of our knowledge of the disease 
is briefly as follows. In 1878 Hartig published a detailed 
account of his investigations on the fungus (which he 
called Trametes radiciperda). His paper is chiefly concerned 
with details of timber rotted by the fungus and its mode 
of attack. He recognized two methods of infection, (i) by 
spores of the fungus and (ii) by the contact of diseased roots 
with living roots, and proposes combative measures which are 
suggested by the results of his researches. Apparently he 
never found Fomes annosus growing on larch, though he 
suspected that this tree might also be attacked. But Hartig 
did not clearly distinguish between the two forms of disease 
for which the fungus is responsible, and since larch trees 
are seldom killed by it, he may have overlooked the heart- 
rot. He states that in Germany Pinus sylvestris, P. strobus, 
Picea excelsa, Abies pectinata, and Juniperus communis are 
the species which are most frequently attacked. It is 
commonest in young plantations, but trees as old as one 
hundred years may succumb to it. In 1889 Brefeld ' carried 
out an exhaustive investigation of the fructifications, the 
germination of the spores, and artificial cultures. He was 
the first to discover the conidia, which are produced in great 
profusion in cultures but have rarely been found under 
natural conditions. On account of the similarity between 
the conidia and basidiospores, and between the organs 
which bear them, he renamed the fungus Heterobasidion 
annosum, thereby creating a new genus which has not been 
perpetuated. On questions of prophylaxis he was funda- 
mentally opposed to Hartig’s doctrines, and the divergence 
of opinion was not softened by the caustic style of Brefeld’s 
1 Oskar Brefeld was born in 1839 at Telgte, in Westphalia. He succeeded 
R. Hartig as professor of botany at Eberswalde in 1878, and proceeded in 
1884 to Minster, and in 1898 to Breslau. His researches on fungi have 
included the cultivation in pure cultures of an immense number of different 
species, and he has thereby discovered conidial forms of reproduction in 
many species in which they were previously unknown. He has also 
brought methods of cultivation to a high degree of excellence, and was 
the first to introduce gelatine as a medium for cultures (New International 
Encyclopedia, iii, 1910). 
