360 DIVISION III. MODE OF LIFE OF THE FUNGI. 



conceded that a predisposition for the attack of a parasite may in some cases be a 

 sickly one, especially if there are deviations at the same time from the condition 

 which we are accustomed from experience to consider the healthy condition in the 

 particular species. But it is also evident, on the other hand, that the predisposition to 

 the attacks of parasites does not always show a sickly condition of the plant, not for 

 instance when there is no parasite present. The real state of things must be investi- 

 gated and determined case by case. 



It was shown by many examples in the morphological portion of this work, that 

 the parasite is either an endophyte and lives inside the organs or even the cells of the 

 host, or is to a great extent an epiphyte on its outer surface. A purely epiphytic mode 

 of life, in which the parasite rests on or is attached to the outer surface of the host, is 

 comparatively rare if we disregard the case of the Lichen-fungi to be described in 

 section CXV ; the Laboulbenieae (page 263) and Melanospora parasitica * and perhaps 

 also those Chytridieae which are said only to rest on their, host may be mentioned 

 as examples of this kind. Other epiphytes, as Erysiphe, Piptocephalis, and Syn- 

 cephalis, enter the interior of the host at least by the haustoria which they send into 

 it. .Chaetocladium adhering to its host and with its tubes in open communication 

 with those of the Mucor which serves as its host does not strictly come into either of 

 the two categories (see on page 20). Either designation may be applied to the 

 Fungi which spread in the deric tissues of the higher animals. 



After these preliminary remarks we may proceed to consider the phenomena 

 of adaptation above indicated under three general heads : i. The attack of the 

 parasite on its host, that is, the first beginning of the occupation. 2. The course 

 taken after occupation by the further growth of the parasite. 3. The reactions oj 

 the host after its occupation and the results of the reciprocal action of the two symbionts. 

 It is owing to the nature of the subject-matter, that though the three questions are 

 kept theoretically distinct from one another, the answers to them must necessarily 

 travel out of the domain of one question into that of another, and especially from the 

 second to the third. 



SECTION CII. The parasitic Fungus attacks its host by means of its spores, 

 or of the germ-tubes emitted by the spores, or of the hyphae developed from the 

 germ-tubes. 



The first case, in which the first attack is made by the spore before germination, 

 is confined to a comparatively small number of epiphytic species, which will be 

 noticed again in another connection at the conclusion of the paragraph, and to certain 

 facultatively parasitic and facultatively endophytic species of Moulds, namely, the 

 pathogenous Aspergilli and Mucor-forms (M. rhizopodiformis and M. corymbifer) 

 which have been studied by Lichtheim 2 . These Fungi are developed in the internal 

 organs of warm-blooded animals, when their spores find their way into the blood- 

 passages and are carried by the blood to suitable spots ; wounded places therefore, 

 though of very small extent, are always in the natural course of things the parts where 

 the endophytically developed Fungus first makes its attack. These forms are actually 

 known as true endophytes only from artificial injection usually of a large number of 



1 O. Kihlman, as cited on page 262. 



2 As cited on page 349, and in Zeitschr. f. klin. Medicin, VII, Heft 2. 



