18 SCHMIDT OX THE COMPARATIVE PHYSIOLOGY 



tained by means of potash. The peculiarity of the products of 

 distillation caused Odier to overlook the nitrogen present; as 

 this was evolved as acetate of ammonia mixed with free acetic 

 acid, no alteration in the colour of the red litmus paper could 

 occur. 



However, it is easily seen that this substance is principally 

 shown to be peculiar by negative characters ; the cortical sub- 

 stance of the hair, skin, nails and epidermic scales of the Verte- 

 brata are soluble with difficulty in potash, and its peculiarity 

 could only be considered as proved when all the analyses of the 

 substance obtained from different organs and animals agreed. 

 I therefore subjected the entire tegument of the Cockchafer, 

 after removing the intestinal tract, as also the tegument and 

 elytra of Ateuchus sacer, to the same treatment ; by this means 

 we should moreover ascertain whether the winged inhabitants of 

 Algiers produce the same chemical substance, notwithstanding 

 the difference in food and climate. The following are the ana- 

 lytical results : — 



a. Melolontha. Elytra alone. 

 Determination of the Ash. 

 0'206 of the substance gave 0"001 ash = 0*5 per cent. 

 Nitrogen. 



I. 0*317 substance gave 0*3 18 ammonio-chloride of platinum 

 = 6'33 per cent, nitrogen. 



II. 0*403 substance gave 0*429 ammonio-chloride of platinum 

 = 6*72 per cent, nitrogen. 



Combustion. 

 0*292 substance gave 0*4975 carbonic acid and 0*175 water, 



, , r Carbon. . 46*69. 



hence per cent. < tt i c.nn 



^ \^ Hydrogen 6*69. 



b. Melolontha. Elytra, wings and cutaneous tegument. 

 Determination of the Ash. 

 0*271 substance gave 0*0018 ash = 0*664 per cent. 

 Nitrogen. 



I. 0*366 substance gave 0*3685 ammonio-chloride of platinum 

 = 6*36 per cent, nitrogen. 



II. 0*418 substance gave 0*4285 ammonio-chloride of plati- 

 num, = 6*48 per cent, nitrogen. 



