118 Mortier F. Barrus 



it did not occur to any extent. Atkinson (1895) says that septation 

 occurs unless the spore is very short, and that the spore becomes con- 

 stricted at the point of septation soon after germination. He observed 

 an increase in the size of the spores after germination until they became 

 several times larger than at first, and states that even with spores which 

 fail at first to germinate a similar increase in size takes place, and they 

 become uniseptate, strongly constricted at the septum, and richly charged 

 with highly refringent granules. Edgerton (1910:19) states that the 

 spores swell but slightly or not at all in germinating in nutrient media 

 if they are scattering, but if they are abundant and close together in the 

 culture medium they swell to two or three times normal size in some 

 cases. During the process of enlargement a septum is formed, and with 

 further swelling a constriction of the spore appears at this point. Edgerton 

 finds that "when there are more than 12 or 15 spores to the cubic milli- 

 meter of medium, the spores become swollen, germinate slowly and but 

 poorly. When the number is less than this, they germinate with but 

 little, if any, swelling" (page 20 of reference cited). He thinks this may 

 be due to an enzyme prohibiting growth, given off by the spore during 

 germination. Dey (1919) observed that if the drop of water used in the 

 culture had a convex surface, the spores lying in the middle hardly germi- 

 nated while most of those at the border did. He thinks this difference 

 is due to a difference in the oxygen supply. 



The germination of the spore in water consists, in most cases, of the 

 production of an appressorium at one or both ends of the conidium (Plate 

 III). This is a subglobose body flattened on one side, having dark- 

 colored, thick walls and containing dense granular protoplasm. It often 

 appears attached directly to the conidium or is produced at the end of 

 a short germ tube, although it is not uncommon to find an appressorium 

 at the end of a long, narrow hypha. In the ordinary process of germi- 

 nation in nutrient media, the spore contents become coarsely granular 

 and the vacuole increases greatly in size or there may be several vacuoles. 

 In rain-water cultures, the spore contents during germination seem to 

 pass into the appressorium, in which the protoplasm appears to be very 

 dense. 



The appressoria in most cases are closely appressed to the slide. A few 

 have been noticed, however, which were apparently free, as they were 

 observed to move when the slide was jarred. In the course of twenty-four 



