414 DR. D. D. CUNNINGHAM ON THE CONIDIAL 
is, judging from MM. Van Tieghem and Le Monnier's experience, capable of giving 
excellent practical results. Working here, however, I have found that with many fungi 
it is impossible to provide suffieient nourishment in this way or, at all events, to furnish 
all the conditions necessary for complete development. A luxuriant mycelium is often 
produced, but fructification is seldom freely developed unless extra nutritive material be 
added; and the process of introducing this into the cell practically reduces the cultiva- 
lion very much to one carried out on M. de Bary's method, where the spores are kept 
under continuous observation in a moist chamber containing both the microscope and 
cultivation. The cellular method, where successful, may allow of conclusions being more 
rapidly arrived at; but the other, when carried out with sufficient care, and repeated 
often enough, gives results which are very nearly, if not quite, as good. ic 
The medium employed in the cultivations in the present case consisted of fresh decoc- 
tions of the corolle of Hibiscus, and, in one or two instances, of boiled water alone. 
The ripe conidia are obovate in form, and, as previously mentioned, generally have a 
small projeetion at the narrower extremity, formed by the tip of the parent sterigma 
(fig. 6). They vary considerably in size, but average specimens measure about 0'02 ` 
millim. by 0:011 millim. They consist of a purplish-brown exospore, containing a mass of 4 
granular protoplasm invested by a delicate endosporic layer. They present no distinct 
indications of a nucleus, either when first detached from the sterigmata or during the 
course of germination; but a clear space or vacuole may be present in the protoplasmie 
contents. When sown in water no change takes place in them, and germination does — 
not occur. On their introduction into Hibiscus-decoction, the first phenomenon observed ` 
is the commencement of movement among the granules of the protoplasm. This begins 
almost immediately, and very soon attains considerable activity; the streaming of the 
protoplasm is in fact established so far as the limited area of the interior of the conidium ` 
will allow of such a phenomenon. A certain amount of enlargement of the cell now ` 
occurs; but this is slight as compared with that taking place in many Mucorini. In 
two cases in which the increase was measured the conidia, when first sown, were 0-018. * 
by 0:012, and 0:02 by 0:012 millim.; and on germination were 0:02 by 0:02, and 0:02. : 
by 0015 millim. As a rule there is little or no increase in the length of the cell, but ` 
the transverse diameter increases until it nearly or quite equals the longitudinal one ` 
and the entire body assumes a spherical form. ` 
The germinal tubes next make their exit. This process takes place very soon; in one 
case, where special observations were taken in regard to this point, some of the tubes had Er 
already attained a length of 0:025 millim. half an hour after the conidia were sown. 
The precise time of emission, however, varies, being considerably delayed in the case of 
conidia which have been kept for any length of time previous to being sowed; but 
germination usually occurs, at latest, within five hours, and, as a rule, takes place much : 
sooner. The majority of conidia give origin to one or two tubes only; but in rare ` 
instances three are produced. The phenomena attending germination vary somewhat ` 
with the ripeness of the conidia. In immature specimens the exospore shows no distinct "s 
evidenees of rupture, but appears rather to be pushed in front of the protruding tube 
and to blend Acc with it. „Where, Aron the o conidia a are v iespughir ripa 
