236 ANNUAL OF SCIENTIFIC DISCOVERY. 



ducing 600 kilogrammes of scales, worth 25,000 francs; and all this 

 is employed exclusively in the preparation of artificial pearls. 



Nothing is known concerning the chemical nature of this substance 

 which is attached to the scales of this little fish, and no one appears 

 to have devoted any attention to that point. Mr. Barreswil has, 

 however, discovered that it is identical with a principle extracted 

 directly from guano by Bodo Unger, which he called Guanine. 

 Guano being an excrement of sea-birds, it follows on the one hand 

 that the guanine might be met with in other species of fish besides the 

 ablette, a thing which was to have been expected. Interesting in a 

 physiological point of view is the question, what is this proximate 

 principle which is not digested, and which is found unchanged in the 

 excrements after they have been for many ages exposed to the action 

 of the air? Silliman's Journal, Correspondence of M. Nickles. 



USES OF TEA IN THE HEALTHY SYSTEM. 



In a paper recently read before the London Society of Arts, on 

 the above subject, by Dr. Adam Smith, the author recommended the 

 use of tea, as beneficial, in the following cases : after a full meal, 

 when the system is oppressed with food ; for the corpulent ; for the 

 old ; for hot climates, and especially to those who, living there, eat 

 freely, or drink milk or alcohol; in cases of suspended animation; 

 for soldiers, who, in time of peace, take too much food in relation to 

 the waste proceeding in the body; for soldiers and others marching 

 in the heat of Eastern climates, for then, by promoting evaporation 

 and cooling the body, it prevents in a degree the effects of too much 

 food, as of too great heat. For this purpose, a cold infusion may be 

 made, and a quantity equal to twenty-five grains of tea should be 

 taken often during exposure. 



POISONING OF NOXIOUS ANIMALS. 



On account of the numerous accidents which have occurred from 

 using arsenic and phosphorus for this purpose, M. Severin Causse, 

 at the request of the French government, has been pursuing a series 

 of investigations with the object of devising some means of poisoning 

 which should be as efficacious and more safe than those in use. As 

 general principles he lays down these rules : 1 . That we must not 

 risk mistakes by employing the poison in the form of biscuits, pills, 

 or powder. 2. An excipient must be used which is repugnant in 

 taste to man but not to animals. 3. Emetic substances should be 

 added, so as, in case of the poison being swallowed accidentally, 

 vomiting may be produced, which is not with gnawing animals, like 

 rats and mice. 4. The substance should be easily detectable by chem- 

 ical analysis. 5. The composition he finally recommends, as best 

 suited as a destructive agent, consists of tallow 886 grammes, tartar 

 emetic 153 grammes, and euphorbimn 51 grammes. 



ARTIFICIAL ALIZARINE, THE COLORING PRINCIPLE OF MADDER. 



At a late meeting of the Paris Academy, M. Dumas made the im- 

 portant announcement that M. Roussin, a French chemist, had sue- 



