Chapter XIV 



— 159 



The Vacuolar System 



or alcohol, is stained deeply red by aniline blue or violet basic 

 dyes, as well as by haematein. It consequently shows a whole 

 series of histochemical reactions which are very well known and 

 are very different from those of the chondriosomes. 



It is, therefore, well established that there does not exist the 

 slightest relation between the chondriome and the vacuolar sys- 

 tem; they are two independent systems which are coexistent in 

 the cell. There is between the young stages of the vacuoles and 

 the chondriosomes merely a coincidence of form. This close re- 

 semblance exists, however, only in a very limited phase in the 

 development of the vacuoles and seems to be explained by the fact 

 that the vacuoles are at that moment in a semi-fluid physical state 

 which is closely allied to the physical state of the chondriosomes. 



Physical characteristics of the 

 vacuoles:- The chondriosome- 

 shaped vacuoles seem to be of semi- 

 fluid consistency and in a physical 

 state which approaches that of 

 the chondriosomes. Ultramicro- 

 scopic examination shows that in 

 general the chondriosome-shaped 

 vacuoles are no more visible than 

 the chondriosomes (Fig. 109). In 

 certain cases, however (teeth of 

 young rose leaflets, barley and 

 wheat roots), it is possible to dis- 

 tinguish them. They appear optic- 

 ally empty and are visible only be- 

 cause of their faintly luminous 

 contours, i.e., when they can be 

 seen, they show the same charac- 

 teristics in this respect as do the 

 chondriosomes and the plastids. 



Fig. 103. — a, Cladophora; vital staining 

 of large central and small peripheral 

 vacuoles. 6, c, Ulothrix pseudo-ftocca; 

 arrangement of vacuoles in b vegetative 

 cells and in c zoosporangium. d, e. 

 Cladophora; zoospores which have ceased 

 swarming. /, Bryopsis plumosa; zoospore. 

 g, Ulva Lactuca; zoospore which has just 

 come to rest, at, stigma. (After Dan- 



GEARD). 



With the chondriosomes and the 



plastids, they might be classified as a coacervate system. 



The liquid vacuoles, derived by swelling from these chondrio- 

 some-shaped vacuoles, also appear optically empty even in cases 

 in which they enclose an abundance of colloidal substances (tan- 

 nin, metachromatin). Rather infrequently they are visible by 

 reason of their faintly luminous contours. Certain indirect meth- 

 ods, however, often make it possible to locate their position. Thus 

 in the yeasts, there exist in the cytoplasm bordering on the vacu- 

 oles, numerous lipide droplets which appear very luminous and 

 because of them the position of the vacuoles may be easily detected 

 (Fig. 110). There sometimes appear within the vacuoles strongly 

 lighted granules which show Brownian movement, but these are al- 

 ways visible in direct lighting and are not of the order of micelles. 

 The vacuole, then, in its liquid state seems to be composed either 

 of a colloidal solution whose micelles are very small and not 



