Chapter XIV 



157 — 



The Vacuolar System 



seem to be encountered in all cells in all phases of development and 

 that, in general, they appear in embryonic cells as minute elements 

 composed of a very concentrated colloidal solution and that they 

 sometimes show a great resemblance in form and dimensions to 

 the chondriosomes. These chondriosome-shaped elements swell and 

 are transformed into large liquid vacuoles containing very dilute 

 colloidal solutions. These facts do not, however, confirm Dange- 

 ard's interpretation in which he identifies the vacuolar system 

 with the chondriome. Although in some cells the young vacuoles 

 present forms almost identical with those of the chondriosome^, 

 there are other very numerous cases in which the young vacuoles, 

 on the contrary, have an appearance which does not permit of any 

 confusion with the chondriosomes. For example, in some algae, 

 the vacuoles remain constantly in the 

 state of large liquid inclusions. Nev- 

 ertheless, since it is evident that 

 these two categories of elements may 

 sometimes be easily mistaken for one 

 another, it is advisable to examine 

 here the characteristics which make 

 it possible to distinguish between 

 them. 



hhpf^ 



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Fig. 101. — Penicillium glaucum. 

 Vital staining with neutral red. 1-5, 

 filaments; one or more large, deeply 

 stained bodies precipitated in the 

 vacuole by the dye; small vacuoles in 

 branches seen to form de novo. 6- 

 19, germinating conidia; small vacu- 

 oles in germination tube seem to 

 form de novo. 



Chondriosome-shaped vacuoles and 

 chondriosomes. Characteristic dif- 

 ferences:- The vacuoles, even in 

 their chondriosome-shaped state, are 

 essentially distinct from the chon- 

 driosomes in their histochemical 

 characteristics. An inherent differ- 

 ence rests in the fact that although 

 the vacuoles stain deeply with vital 

 stains (neutral red, cresyl blue, Nile 

 blue, etc.), the chondriosomes, on the 

 contrary, have no affinity for these dyes and are not colored in the 

 living state except with special stains (Janus green. Dahlia violet, 

 methyl violet), which usually show no marked affinity for the 

 vacuoles. Besides, as has been seen, staining of the vacuoles is 

 essentially a vital phenomenon and ceases when the cells are killed. 

 On the contrary, the chondriosomes stain only temporarily; their 

 coloration is stable only in dying cells and is then always accom- 

 panied by vesiculation, a state soon followed by the death of the 

 cells. The coloration persists, even after the death of the cell. 

 Meristematic cells may be found in which chondriosomes are vis- 

 ible in the living state and the independence of these from the 

 vacuoles may be made certain by vital staining, since the chondrio- 

 somes remain unstained. The same observation may be made for 

 the Saprolegniaceae in which the chondriosomes are always clearly 

 visible in the living state in all stages of development of the plant. 

 We have obtained, furthermore, in these and other fungi (Endo- 



