| Comments |
P.9 2nd paragraph: "Plasma Volume. The circulating plasma volume is usually determined by a substance, such as T 1824 (Evans Blue), that binds to plasma proteins, or as the distribution volume of radioactively labelled serum albumin (RISA). Plasma volume may also be calculated indirectly from the red-cell volume, as determined by labelling with Cr51 and haematocrit. The plasma volume has been measured by these methods in several species of birds, both marine and terrestrial (Table 1.3). Birds of a fairly large range of body weight have been investigated, but information is lacking on species of less than 100 g. The determinations in marine birds range from around 5% to 7% of body weight whereas those of terrestrial species range from 3%-4% to 5%. A large number of species must be examined before firm conclusions concerning a possible difference can be drawn. A range around 5% is usually observed in mammals. A large blood volume might be an advantage for diving birds (Bond and Gilbert 1958). If the difference between marine and terrestrial birds is real, it may, however, be related to factors other than diving, as the highest value seems to be recorded in a gull (see Table 1.3). Conspicuous sex differences have not been encountered." |