MOLDS 



45 



PenicUlium, the metachromatic corpuscles are produced in great 

 abundance (Fig. 29, 26 and 30), then graduaUy disappear as the conidia 

 from (29, 3). Here again they serve as food for the conidia. 



Metachromatic corpuscles appear not only in the vacuoles, but also 

 in the perivacuolar cytoplasm. There they spring up, to diffuse finally 

 in the vacuole where they increase. It is difficult to observe their 

 manner of forming in the mycehal filaments, but in the preparation for 

 sporidation some molds (asci of the 

 higher Ascomycetes), it has recently 

 been demonstrated that they start 

 in the midst of the elements of the 

 chondrium, which act as plastids 

 similar to the plastids of the higher 

 plants. They start in the interior 

 of the granular-mitochondria or in 

 the rod-mitochondria (Fig. 30). In 

 the former case, a small corpuscle 

 appears in the midst of a mitochon- 

 dria, then develops gradually, while 

 the mitochondrial membrane which 

 envelops it grows thinner; is re.- 

 duced to a small capping of the 

 grain on one side; then disappears 

 when the latter reaches maturity. 



It is noteworthy that the corpuscles emigrate with their plastid to the 

 interior of the vacuoles during their development. 



When the corpuscles start in a rod-mitochondrium, at the junction 

 of these rod-mitochondria several small corpuscles are seen to form, then 

 the parts of the rod-mitochondrium which join are absorbed and the 

 corpuscles, enclosed in their mitochondrial membrane, once separated, 

 undergo the same evolution as above. 



Thus the metachromatic corpuscles, like grains of starch in 'the 

 higher plants, start in the midst of the mitcohondria and develop 

 gradually out of their mitochondrial matrix, and with the aid of the 

 vacuolar substance. 



In molds are found still other reserve products. . One often sees 

 globules of fat in the cytoplasm, which are easily stained a black- 

 brown by osmic acid; and glycogen which can be differentiated by iodine 



Fig. 29. — Conidial organ of ^j^er- 

 gillus niger with metachromatic 

 corpuscles. 



