ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 243 



Appearance of Fat in Human Thymus.*— Th. Herrmann discuss* s 

 the time of appearance of the fat in the thymus. It is well known that 

 fatty tissue increases daring the normal involution until the thymus 

 fatty body is formed which has only slight, structureless, functionless 

 remnants of the gland. The fatty tissue is developed in the child 

 between the lobes of the thymus. In ninety-two cases examined, either 

 foetal or newly born, fatty tissue was found only in seven. It appears 

 in the peripheral portions of the connective-tissue septa between the 

 thymus lobes. In some cases fatty tissue was found in embryos 42 cm. 

 in length, but in the great majority the fatty tissue develops after birth. 



c. General. 



Nutrition of Marine Animals. — B. Moore, E. S. Edie, and E. 

 Whitley f have investigated the nutrition and metabolism of marine 

 animals with especial reference to what nutritive material can be 

 obtained from dissolved organic matter in the water. They have 

 especially investigated the rate of oxidation and the output of carbon- 

 dioxide in relation to the available food supply in the sea-water. Their 

 experiments definitely settle that sea-water does not contain any 

 appreciable amount of organic matter capable of acting as a nutrient 

 medium for aquatic animals. The preponderating amount of food 

 consumed by larger marine animals is utilized for increases of the 

 animal by growth and for sexual reproduction, and but a small fraction 

 is oxidized for the metabolic needs of the animal in other activities 

 than growth and reproduction. 



B. Moore and G. A. HerdmanJ have, in the same connexion, studied 

 the effects in the lobster of prolonged abstention from food in captivity. 

 Lobsters provided daily with a sufficient supply of fresh sea-water can 

 be preserved alive without food during a period of over seven months. 

 The live body-weight of such lobsters does not diminish during such a 

 prolonged period of inanition. But while the actual weight of inorganic 

 matter remains constant, the total dry weight and total organic weight 

 are markedly diminished, and as a result the percentage of inorganic 

 matter in the dry weight becomes increased. The total oxidizable 

 organic matter may fall to considerably less than one-half of the initial 

 amount. At the commencement of the period, protein, fat, and carbo- 

 hydrate are oxidized almost equally, later the carbohydrate becomes 

 exhausted, and although fat is still present, nearly all the oxidation falls 

 upon the protein. There is a satisfactory correspondence between the 

 amount of oxygen consumed by the animals throughout the period and 

 the amount of organic matter disappearing. The oxygen consumed 

 corresponds very closely to that required for oxidation of the organic 

 matter disappearing, so that there is no reason to suppose that the 

 animal utilizes any dissolved organic matter which might hypothetically 

 be present in the sea-water. 



The rate of oxidation is throughout a slow one, representable by 



* Anat. Anzeig , xlvii. (1914) pp. 357-9. 



t Rep. Lancashire Sea-Fisheries Laboratory, xxii. (1914) pp. 297-320. 



t Rep. Lancashire Sea-Fisheries Laboratory, xxii. (1914) pp. 321-9. 



