38 



LEECHES 



as 15 cal per day at 18°C. During starvation the leech utilized 

 the stored carbohydrates and fats and its energy consumption 

 dropped to about 7 cal per day. 



When a meal of blood has been sucked into the crop it first 

 thickens, water being abstracted and passed out via the nephridia 

 together with considerable quantities of sodium chloride. Worth 

 (1951) reported that when land leeches are feeding they become 

 surrounded by a pool of clear fluid. This is presumably a nephridial 

 excretion. In Fig. 22 is shown that in Hirudo the weight of blood 



100 



10 



20 30 



Days after feeding 



Fig. 22. Reduction in weight of Hirudo due to excretion of 

 water after feeding. Drawn from data in Busing et al.f 1953. 



in the crop decreases by more than 40% in ten days. The haemo- 

 globin soon becomes deoxygenated but the erythrocytes remain 

 intact for a very long time. So remarkable is the freedom from 

 putrefaction that intact erythrocytes have been found 18 months 

 after ingestion and even white corpuscles and pathogens may be 



