The Cultivation of the Fungi. 315 
and no pileus is developed in the latter, while in C. nycthemerus, 
not even the first beginning of the development of the pileus can 
take place in the absence of light. 
Reference has already been made to the influence of higher 
temperatures on the germination of certain fungus-spores, and 
there are several forms which require an increased temperature for 
developing their fructifications, principally those which are parasitic 
on warm-blooded animals. 
The method of obtaining hanging-drop cultures containing 
single spores, a method which, as already mentioned, Brefeld was 
the first to adopt, is fully described. In employing this method 
with very minute spores which are difficult to find and observe, 
except under the higher powers of the microscope, the work may 
be facilitated by leaving the spores in a nutrient solution until the 
swelling which usually accompanies the first stages of germination 
takes place, when the spores are more easily seen. In dealing 
with spores which are wetted only with difficulty and hence show a 
tendency to cling together in groups on the surface of the liquid, 
keeping the spores for a time in a saturated atmosphere before 
transferring them to the liquid will usually overcome this 
disadvantage. 
The growth of a fungus-mycelium in a hanging-drop culture 
may be prolonged after the food-material in the drop is exhausted, 
by absorbing the remaining liquid with a piece of sterilised filter- 
paper and adding a fresh drop of a nutrient solution. 
Lastly, the various methods of artificial infection of the host- 
plant employed in working out the life-history of a parasitic fungus 
are described in detail. 
The second and larger part of this volume deals principally 
with the special applications of the general methods of cultivation 
already considered to each of the different groups of Fungi. These 
applications are too varied to be noticed here and the reader must 
be referred for information to the volume itself. A general 
comparative account is also given of the morphology and biology of 
each group, and the evolution of and connection between the various 
forms of fructification, and the employment of these characters in 
classification are discussed. 
One very useful feature in this part of the volume is that 
indications are frequently given where uncertainty or gaps exist in 
our present knowledge of the subject, and hence where research 
may be profitably directed. 
Brefeld’s well-known views on the phylogeny of the higher 
Fungi, which have frequently been put forward in his many 
publications, have, as is usually the case where questions of phylo¬ 
geny are involved, led to much controversy and have been opposed 
by more than one conflicting opinion. They have been so often 
fully discussed elsewhere that it is unnecessary to enter into them 
here. 
Suffice it to say that his idea of the origin of the ascus of the 
Ascomycetes from the sporangium of the Phycomycetes, in spite 
of its attractiveness, has not met with general acceptance, being 
opposed principally on cytological grounds. Furthermore, Brefeld 
refuses to recognise any sexual process as occurring in the 
Ascomycetes proper, with the exception of the nuclear fusion which 
