EFFECTS OF THIRST, ETC., ON EMYS TERRAPIN. 



43 



Sources of error, however, have heen avoided, as far as possible, by first investi- 

 gating the blood of cold-blooded animals in a normal state, and then performing an 

 extensive series of experiments upon the effects of a deprivation of food and water. 

 It would have, undoubtedly, added to the accuracy of these experiments, if we 

 could have noted the changes, from time to time, going on in the blood of the same 

 animal. This would have been practicable with the alligators, if they could have 

 been obtained alive. These animals are found in our swamps, marshes, lagoons, 

 and rivers. Their place of habitation is often of difficult access, and very unhealthy 

 in the summer season to the white man, and the reptiles themselves are shy, and 

 can therefore but rarely be obtained in a living state. A shot, from a rifle, in the 

 head (the only vital part), destroys the life, and before they can be carried home, 

 the blood is unfit for analytical examination. In a morning's hunt I have mortally 

 wounded five or six without obtaining a single one, for they all sank in deep water. 



With reference to the Terrapins, they are generally so small that the extraction 

 of the amount of blood requisite for only two analyses, would materially affect the 

 final result. We have, accordingly, been compelled to choose between two evils. 



By multiplying these observations, as accurate results, we think, have been 

 obtained as if the same cold-blooded animal had been used during the investigation. 



We hope that those who may have occasion to follow us in our researches, will 

 make due allowance for the difficulties with which we have had to contend. 



Series II. — Effects of Starvation and Thirst upon the Blood of the Salt- Water 



Terrapins {Emys terrapin). 



23. Blood of an Emys terrapin, in a normal condition, having been captured only 

 twelve hours. July 3. 



The serum was of a golden color, resembling that of the Emys serrata, Emys 

 reticulata, and Cathartes atratus. 



Amount of blood obtained, about 1000 grains. 



Solid constituents in 1000 parts of blood 

 " " " " serum 



" " in serum of 1000 parts of blood 



"Water in 1000 parts of blood 

 " " serum 



1000 parts of blood contained — 



Water ..... 

 Blood-corpuscles (dried organic constituents) 

 Albumen, fatty and extractive matter 

 Fibrin ..... 

 Fixed saline constituents 



1000 parts of blood contained — 



( "Water 

 Moist blood-corpuscles 441.28 i ,., 



(Solid constituents 



Liquor sanguinis 



552.t2 



(Water . 



1 Solid constituents 



154.72 



43.83 



38.15 



845.28 



956.17 



845.28 

 103.82 



36.01 

 4.15 



10.74 



335.46 



111.82 



509.82 



42.90 



