64 Papers from the Marine Biological Laboratory at Tortugas. 



a significant r61e in maintaining the weight of the medusa when starved in 

 daylight, but further experiments have shown that this is not the case, 

 for the medusae sometimes starve at a more rapid rate in diffuse daylight 

 than in the dark, although the reverse is usually the case. 



It is not the object of this paper to present an exhaustive review of all 

 previous researches upon the metabolism of inanition in invertebrates, 

 because previous studies do not touch upon the chief subject of this study — 

 the law of the decline of weight. A brief mention of certain important 

 sources of general information should, however, be presented. 



The earliest work appears to be that of Dumas and Milne-Edwards 

 (1820, Annales Chim. et Physique, tome 14 ; and also in the Comptes Rendus, 

 Paris, 1843, tome 17, p. 531) upon the metabolism of bees. 



Peligot (1865, Comptes Rendus, tome 61, p. 866; and 1867, Annales 

 Chim. et Physique, tome 12, p. 445) studied silkworms in the same connection. 



Especially worthy of mention is the work of Slowtzofif^ (1904), who found 

 that when starved the vineyard slug consumed about 25.74 P^^ cent of its 

 total weight and about 28.41 per cent of its store of energy. The relation 

 between the organic and inorganic substance remains the same in the 

 normal and in the starved animals. The loss of vital substances consists 

 of fat, carbohydrates, and water in the proportions of carbohydrate 93.98 

 per cent, fat 78.51 per cent, and water about 30.02 per cent, while the loss 

 of albumen was computed to be 23.70 per cent. As a result of starvation 

 the soft parts of the animal acquire an increase of insoluble salts to about 

 35.9 per cent. During the period of starvation the slugs consume 4.84 

 calories of energy per kilogram of their weight per 24 hours. The phos- 

 phoric albumens were largely retained, only about 19 per cent of these 

 being parted with. 



In 1 901 the same author^ starved the dung beetle, Geotrypes stercorarius 

 and found that in from 5 to 11 days it lost about 21 per cent of its original 

 weight, the loss appearing to be chiefly water and fat. 



Schulz^ starved Planaria lactea and states that after 6 months without 

 food some of the worms were reduced to about one-tenth their original 

 size. There were, however, considerable individual differences, some of the 

 animals being three times as large as the smallest after all had starved for 

 6 months. Schulz made a histological study of the starved worms and 

 found that some of the cells were killed as a result of the starvation, while 

 others had degenerated or become reduced in size. The epithelium tends 

 to fuse and its cells to degenerate into a syncytium, \'ery much as we have 

 observed in Cassiopea. 



Perkins^ observed that the cells of the attached hydroid larvae of Goni- 

 onemus murhachii degenerated in aquaria, where presumably they were 



1 Slowtzoff, B. (1904). Beitrage zur vergleichenden Physiologic der Hungerstoffweclisels, Mittheil. 2, 

 Der Hungerstoffwechsel der Weimbergschnecke (Hofmeister's Beitrage). 



'Slowtzoff, B. (1909). Idem., Mittheil s> Der Hungerstoffwechsel der Mistkafer (,CeotryPes stercorarius). 

 Biochemischer Zeitschrift, Bd. 19, p. 504. 



'Schulz, E. (1904). Ueber Reductionen, I, Ueber Hungerscheinungen bei Planaria lactea. Archiv 

 fiir Entwicklungsmechanik der Organismen, Bd. 18, pp. SSS-S77. Taf. 34, 11 fign. 



♦ Perkins, H. F. (1902). Proc. Acad. Natural Sci., Philadelphia, vol. 54, p. 76s; also: 1902. Biol. Bulletin 

 Woods Hole, vol. 3, pp. 172-180. 



