THE MICROSCOPE. " 59 



Lastly, the chlorophyll-bearing plants consume products of the 

 lower organisms, and having also the property of assimulating urea 

 and inorganic ash constituents. Sewage will finally be destroyed in 

 a river of adequate temperature, unless the natural agents of oxidation 

 are excluded by the addition to the water of chemical refuse fatal to 

 organic life, or unless vegetation is prevented by artificial 

 means. — Ex. 



Hovv^ TO Detect Glucose. — The proportion of glucose added 

 varies from twelve to twenty parts per 100, and there are very few 

 fancy sirups or sugars in the market that are not indebted to the 

 corn crop for their beauty and comparatively low cost. Aside from 

 elaborate scientific tests, the means of detecting this adulteration are 

 very simple. Being less soluble than sugar the glucose settles at the 

 bottom of the cup, unless the hot tea or coffee is persistently agita- 

 ted, and when left to dry forms a hard, horny film, similar to dried 

 gelatine, but a little more readily scraped or cut. Upon the surface 

 of sirup thus adulterated a film or pellicle forms upon exposure to 

 the air. The pellicle is of extreme thinness and tranparency, but 

 becomes corrugated when the exposure is prolonged, and possesses a 

 considerable degree or resistance to rupture. A lens is not neces- 

 sary to its detection and study. These are very simple tests, but 

 they are capable of detecting a very minute per centage of the adul- 

 terant. — Science Gossip. 



Microscopic Examixatiox of Blood. — The characteristic dis- 

 tinctions of human blood and those of the blood of other animals 

 are thus set forth in No. 2 of Z' Orosi by Dr. Vincenzo Pesetty 

 Cervera, and if other physiologists will take the pains to varify his 

 work, they may play a very important part in medical jurispru- 

 dence. When blood is mixed with a little bile, small crystals not 

 over 0.003 of ^ metre in size are formed ; but these crystals the 

 doctor says, will show whence the blood had come. If from man, 

 the crystals will be rectangular prisms ; if from the horse, they will 

 be cubes ; if from the ox, they v/ill be rhombohedrons ; if from 

 the sheep, they will be rhombohedric tablets ; if from the dog, they 

 will be rectangular prisms, closely resembling the human forms ; if 

 from the rabbit, they will be tetrahedrons ; if from the squirrel, they 

 will be hexagonal tablets ; if from the mouse, they will be octahe- 



