A Disease of Currant Canes. 29 



gresses the original spore is soon lost sight of. In most cases the germ-tubes 

 are soon cut off by septa. The protoplasm is at first nearly homogeneous, 

 but soon becomes vacuolate in the older portions of the tube. After having 

 elongated considerably the thread becomes sparinglj^ septate by the forma- 

 tion of cross partitions. In old cultures the older parts of the mycelium 

 are much sepate and filled with vacuoles. The threads soon begin to branch, 

 until finally a spreading mass of densely interwoven mycelium is produced. 



In threads thirty-six hours old, numerous small, short protrusions appear 

 along the sides of the threads near the ends. These at first resemble incip- 

 ient branches, but are usually of considerably less caliber than the main 

 threads. They are as often curved as straight. When the bud is a little 

 longer than the diameter of the main thread, a constriction appears near its 

 base, so that the apical portion soon separates as a secondary conidium 

 (Fig. 6). The base then grows out, so that other conidia are thrown off from 

 the same point in a similar manner, until small clusters are present along 

 the sides and apex of the main hypha. In old cultures these secondary 

 conidia are present in immense numbers. As represented in the figures, the 

 primary and secondary conidia are borne in precisely the same way along 

 the sides and at the apices of hyphal threads. Being alike also, in size and 

 shape, they differ only in that the primary conidia are produced on more or 

 less erect hyphae, arising from the summits of the compact pink cushions 

 formed by the coalesence of hyphal threads. The secondary conidia, on 

 the other hand, are borne on separate hyphae, arising directly from the 

 spores, and thus not forming a compact stroma. Morphologically, how- 

 ever, the two fruit forms are exactly alike. 



Many cultures of the conidia of Tubercularia have been made, in all of 

 which the mode of germination and production of secondary conidia were 

 as described in the preceding paragraphs. Many of the cultures made from 

 fresh material were more or less contaminated by the presence of bacteria or 

 other fungi. In one set, however, plates two and three were pure, being 

 thickly beset with numerous colonies of the Tubercularia alone. From plate 

 three of this series transfers were made with a flamed needle to tubes of 

 sterilized bean stems and potato-agar. At this time the colonies were about 

 four days old, and secondary conidia were present in great numbers. Pieces 

 of agar containing colonies were also transferred to sterilized currant stems in 

 an Ehrlenmeyer flask. 



On the potato-agar growth was rapid and profuse. The surface of the 

 medium was soon covered with a felty growth, many of the hyaline threads 

 extending far down into the mass. On the bean stems, also, the growth was 

 rapid. The surface of the liquid was covered with a hyaline, felty growth, 

 from which many of the threads projected downward as in the agar. The 

 growth on the stems was sparse consisting of a thin weft of hyphae covering 

 the sub.stratum, and forming white flocculent tufts at the ends of the stems. 

 After eleven days growth numerous small, hemispherical heaps or cushions 

 began to appear on the bean stems at various points. These, at first, were 



