PHYSIOLOGY 115 



coined the name and held it to be made up of a nucleic acid. It stains 

 deeply with nuclear dyes. Reichenow (1909) demonstrated that if 

 Haematococcus pluvialis (Fig. 42) is cultivated in a phosphorus-free 

 medium, the volutin is quickly used up and does not reappear. If 

 however, the organisms are cultivated in a medium rich in phos- 

 phorus, the volutin increases greatly in volume and, as the culture 

 becomes old, it gradually breaks down. In Polytomella agilis (Fig. 

 114, c, d), Doflein (1918) showed that an addition of sodium phos- 

 phate resulted in an increase of volutin. Reichenow, Schumacher^ 



Fig. 42. Haematococcus pluvialis, showing the development of volutin 

 in the medium rich in phosphorus and its disintegration in an exhausted 

 medium, X570 (Reichenow). a, second day; b, third day; c, fourth day; 

 d, e, sixth day; f, eighth day. 



and others, hold that the volutin appears to be a free nucleic acid, 

 and is a special reserve food material for the nuclear substance. Sas- 

 suchin (1935) studied the volutin in Spirillum volutans and Sarcina 

 flava and found that the volutin appears during the period of strong 

 growth, nourishment and multiplication, disappears in unfavorable 

 condition of nourishment and gives a series of characteristic carbo- 

 hydrate reactions. Sassuchin considers that the volutin is not related 

 to the nucleus, but is a reserve food material of the cell, and is 

 composed of glycoprotein. Volutin (Jirovec, 1926). 



Starvation. As in all living things, when deprived of food, Protozoa 

 perish sooner or later. The changes noticeable under the microscope 

 are: gradual loss of cytoplasmic movement, increasing number of 

 vacuoles and their coalescence, and finally the disintegration of the 

 body. In starved Pelomyxa carolinensis, Andresen and Holter (1945) 

 noticed the following changes: the animals disintegrate in 10-25 

 days at 22°C. ; body volume decreases particularly during the early 

 days of starvation and is about 20-30 per cent of the initial volume 

 at the time of death; food vacuoles are extruded from the body in 24 

 to 48 hours; the cytoplasm becomes less viscous and many fluid 

 vacuoles make their appearance; crystals and refringent bodies en- 

 closed within vacuoles, form large groups as the vacuoles coalesce, 

 some of which are extruded from the body; crystals and refringent 

 bodies remain approximately constant during starvation and there 



