458 - URINE 



The urine of tortoises has been examined by Magnus, 

 Marchand, and myself. (See vol. i., pp. 196 and 212.) I found the 

 urine of Testudo greeca to possess the following properties and 

 composition : when the animals had taken no food for a long 

 period, they discharged (when lying on their backs) a very pale 

 yellowish green clear urine, with a distinctly acid reaction ; on 

 cooling, it deposited a white sediment, which redissolved on the 

 application of heat; when they had not fasted for a long time 

 previously, they discharged a neutral or faintly alkaline, tolerably 

 clear urine, which exhibited no turbidity on cooling. The spon- 

 taneous sediment dissolved only partly in boiling water, the 

 bi-urates of ammonia and lime remaining undissolved, while the 

 bi-urate of soda dissolved. The presence of hippuric acid could 

 always be detected with great facility in the urine of these animals 

 by either of the methods described in vol. i., p. 194. 



Besides urea and the above named substances, I also found a 

 crystallizable organic matter, that was insoluble in absolute 

 alcohol, but dissolved in alcohol of 82-g- ; but in consequence of 

 the small quantity in which it occurred, I could not minutely 

 investigate it. Fat was always present in appreciable quantity. 

 The acid sedimentary urine contained from 3*014 to 3'584-g- of 

 solid constituents; the average amount of the ash of the solid 

 residue was 52'5-g-; when burnt white, it contained no carbonates, 

 but only phosphates and sulphates with chlorides ; it further con- 

 tained more potash than soda compounds. 



The excrements of insects consist, for the most part, of the 

 remains of the tissues which have served them for food, but they 

 also contain materials which are nowhere else found than in true 

 urine, even when no definite organ for the elaboration of this 

 secretion can be detected in them. 



It has long been known that the red excrements of butterflies 

 contain a very large amount of alkaline urates, and the fact has 

 been recently confirmed hy Heller. I have found that the 

 intestinal contents of butterflies that have been sucking honey 

 often contain free uric acid in very beautiful crystals. The red 

 pigment of the excrement is an oily body, which, when placed in 

 water, separates in minute drops ; in addition to these substances, 

 a little phosphate and oxalate of lime are also present in these 

 excrements. 



In the excrements of caterpillars, vegetable fibre is naturally 

 the preponderating constituent, but they also contain large 

 quantities of chlorophylle and starch; the latter is found not only 



