EFFECTS OF THIRST, ETC., ON CHELONIANS. 



89 



thrown off into the cellular tissue and serous cavities, and discharged by the kid- 

 neys. This shows that there is a tendency to a definite standard of concentration 

 of the blood, and also to a definite proportion of its organic and inorganic constitu- 

 ents, .which nature endeavors to maintain, however varied the conditions. 



The effects of a change of diet upon the quantity, and chemical and physical 

 constitution of the excretions of the kidneys, were strikingly illustrated in these 

 experiments. The following table will present this in a clear light. 





1 criocl 01 



Amount oi 



opeciiic 



Solid con- 



Reaction 

 of urine. 







starvation 

 and thirst. 



urine ex- 

 creted. 



gravity of 

 urine. 



stituents 

 of urine. 



Color of urine. 





Days. 



Grains. 





Grains. 







Female Emys serrata 



n 



442.3 



1011. 



11.33 



Acid. 



Turbid yellow. 



a it 



26 



113. 



1033.5 



9. 





Clear yellow, with 

 chalky precipitates. 



it It _ 



29 



223.1 



1020. 



10.396 





Clear yellow, with 

 precipitates. 



tt it 



31 



141.5 



1017.5 



29.36 





Limpid yellow. 



ti tt 



38 



890.6 



1017.6 



37.34 





Yellow, with heavy 



Male " 













precipitates. 



49 



300. 



1019.4 



13.02 





Yellow, with pre- 



Female Emys terrapin 













cipitates. 



40 



300. 



1015. 



10.4 





Clear yellow. 



It It 



43 



70. 









Cream-colored like 

 pus. 



11 tt 



57 



130. 





8.05 



It 



Clear yellow. 



Female Emys terrapin, de- 













prived of food and drink 















21 days, and then placed 















in fresh water and snp- 















plied with vegetable food 















28 days. 





840. 



1002. 



3.40 



Slightly 



Limpid light-yellow. 



Emys serrata, starved 30 











acid. 



days, and then supplied 















with water and vegetable 















food 42 days. 





2150. 



1000. 



5. 



Neutral. 



Limpid light-yellow. 



Emys serrata, starved 30 













days, and then supplied 















with water and vegetable 















food 60 days. 





2160. 



1004. 



18.64 



Neutral. 



Limpid light-yellow. 



Emys serrata, starved 80 













days, and then supplied 















with water and vegetable 















food (purslain) 88 days. 





2000. 



1000. 



1. 



Neutral. 



Limpid light-yellow. 



From this table we see that the effect of the change of diet was to render the 

 urine much more abundant, and to alter entirely its specific gravity and chemical 

 reactions. 



This subject, however, will be considered in its important bearings, when we 

 come to the investigation of the kidneys and their excretions. 



