Chapter XIV 



— 165 



The Vacuolar System 



quantities of lipides. Furthermore, Buvat reported in the vacu- 

 oles of many roots, the existence of phosphoaminolipide concretions 

 sometimes combined with proteins. 



In the algae, the colloidal substances of the vacuoles are also 

 very diverse. Proteins, tannins and mucilages seem to exist in 

 them but metachromatin and volutin are also frequently found. 

 This last substance, which is also found in the bacteria, especially 

 characterizes the fungi, in which, with the exception of some of 



4 5 



Fig. 110. — Saccharomycodes. (A), under the 

 ultramicroscope; (B), with direct light. A, 1-6 S. 

 Ludivigii. Vacuoles (V) usually invisible; position 

 marked by strongly lighted lipide granules (Gl; 

 A3, B5) surrounding them and corpuscles of 

 metachromatin (C; A2, B2) which they contain. 

 4, contour of vacuole visible. 6, cytoplasm coagu- 

 lated. 7-9, S. pastorianus. B, S. Ludwigii. 



the Phycomycetes (Saprolegniaceae and Peronosporaceae) , its 

 presence is of general occurrence and in which it appears to play 

 the role of reserve product. In fact this substance accumulates in 

 the vacuoles of the epiplasm of the asci of yeasts and of the higher 

 Ascomycetes and is absorbed by the ascospores at the same time as 

 the glycogen and the lipides which are coexistent with it in the 

 epiplasm. Volutin offers histochemical characteristics which as 

 we have seen make recognition of it easy. Its chemical constitu- 

 tion is still not well determined but there are good reasons for 

 supposing that it is formed by a combination with nucleic acid 

 (Arthur Meyer). 



From very recent work of Mile. Delaporte and Mile. Roukel- 

 MAN on yeasts, it seems that metachromatin corresponds to a 

 zymonucleic acid compound which has been extracted in great 

 quantities in yeasts. According to these investigators, the nuclei 

 of these fungi, as well as those of other plants probably, are com- 



