ANIMALS THAT LIVE WITHOUT WATER I7I 



lead suggested by the salt gland, kept them in good 

 health: where others had given the birds fresh water to 

 drink, the Frings gave them only sea water; and their 

 diet of fish and meat scraps was supplemented with ex- 

 cess salt contained in either gelatin capsules or com- 

 mercial tablets (0.8 gm.) every two or three days. If 

 there was evidence of salt deficiency, salt was adminis- 

 tered in amounts su£Bcient to cause abundant nasal 

 dripping, which is indicative of excess salt in the body. 

 It seems impossible to overfeed salt, so effective is the 

 protection afforded by the gland, but without sea water 

 to drink and (in captivity) excess salt in the diet, the 

 loss of salt in consequence of what is perhaps incidental 

 excitation of the gland leads to lassitude, weakness, 

 coma, and death— a syndrome typical of salt deficiency. 

 Inasmuch as water is retained in the body only pari 

 passu with sodium, the primary disturbance in salt de- 

 ficiency is probably excessive reduction of the volume of 

 the body fluids (chiefly the plasma and interstitial fluid), 

 rather than an imbalance between sodium and potas- 

 sium or other salts. 



In the cormorant, secretion has never been observed 

 except after an osmotic load, and with no incidental 

 stimulus to salt loss the bird is therefore not dependent 

 on sea water ingestion. In the albatross, however, either 

 because secretion by the gland is readily induced by 

 stimuli other than sodium excess, or because of the habit 

 of spending so many years at sea, the bird appears to be 

 dependent on the ingestion of salt in excess of that con- 

 tained in its diet of fish, etc., and this excess is available 

 to it, of course, in its natural habitat only in the form 

 of sea water. If other marine birds habitually drink sea 

 water they are probably such forms as the petrel and 

 penguin which feed on invertebrates such as squid, etc., 

 which are osmotically equivalent to sea water and hence 

 afford little derived water during metabolism. 



The success of the Frings' venture is attested by the 

 fact that at the time of writing four out of five alba- 



