114 



as also the cross walls where they meet the outer wall. In making this 

 statement he refers to the episporium and endosporium as constituting two 

 layers of one wall. In some instances the endosporium is clearly seen to 

 extend between, and to separate, the protoplasts (Fig. 11, &Xi while in other 

 cases the protoplasts appear to touch each other ( Fig. 11, a) , yet when the 

 conidial contents are pushed from a crushed conidium there is always a 

 line, though sometimes it is very thin, separating the protoplasts. Since 

 the protoplasts are distinct from each other, and are thus separated by the 

 endosporium, it seems justifiable to assume that this second cell-wall forms 

 the septa, sometimes obvious though very thin, between the protoplasts. 

 Treated with concentrated sulfuric acid the conidial endosporium dissolves 

 rapidly, and by the generated pressure the episporium is ruptured, invari- 

 ably at the basal end first, this often opening trap-door-like, though fre- 

 quently the pressure is sufficient to tear the wall of the conidium open 

 throughout its length. With the solution of the endosporium the proto- 

 plasts issue from the case of the conidium and appear to be unattached. 



The individual protoplasts vary much in shape, sometimes being nearly 

 spherical; in other cases nearly cubical. Each protoplast is surrounded 

 by a differentiated layer which in some cases is so clear, distinct, and thick 

 as to appear to be a third wall (Fig. 11). Perhaps it is. Under gentian 

 violet and many other aniline stains, while the protoplast takes a strong 

 stain this layer refuses to stain. Microtome cross-sections and longitudi- 

 nal sections of conidia verify the foregoing conclusions (Fig. 11, /). In 

 cross-sections (Fig. 11, g), with Fleming's triple stain the protoplast stains 

 as usual, but the second cell-wall refuses to stain; under Bismarck brown it 

 takes a very faint stain. Under action of aniline blue, iodine, fuchsin, mal- 

 achite green, Pianese, or chlor-zinc-iodine it remains unstained. In longi- 

 tudinal sections cut so thin that two sides of the conidium have been cut 

 away, mature conidia show no continuity of the protoplasts (Fig. 11, d). 

 When plasmolized the protoplasts all shrink and lie quite separate from each 

 other, and it is in such condition that the appearance of a third conidial 

 wall is most evident (Fig. 11, a, b) . Previous to plasmolysis the proto- 

 plasts are frequently seen to touch each other on the median longitudinal 

 axis of the conidium, and a very faint line (plane) is observable extending 

 across the conidium (Fig. 11, a, b). This probably represents the true 

 septum, following nuclear division. The protoplast wall bears a small 

 dot-like thickening (Fig. 11, e) adjacent to its sister protoplast, which may 

 also be residual evidence of nuclear mitosis. 



The characters as here given for H. No. 1 are found also in such re- 



