ZOOLOGY. 345 



oxydized. An exception was also referred to in the animal kingdom, in 

 which fat is supposed to be formed by the deoxydation of sugar, but attention 

 was drawn to the fact that this process admitted of another explanation not 

 opposed to the physiologico-ohemical distinction pointed out. These processes 

 were further shown to be connected with the relations existing between the 

 animal and vegetable kingdoms. The plant was produced from mineral 

 compounds carbonic acid, water and ammonia the substances out of which 

 the animal was formed; and no instance was known of the animal appropri- 

 ating and forming organic substance out of these compounds. This was the 

 distinguishing feature of the life of the plant, and the liberation of oxygen 

 gas its most constant result. The appropriation of substances thus formed, 

 and the uniting them once more to oxygen was the distinguishing feature of 

 animal life, and the formation of carbonic acid gas its most constant result. 

 Minor changes occurred ; but these were the grand distinguishing features 

 of the two kingdoms, the recognition of which by structure, function, or 

 results, could alone enable us to distinguish between plants and animals. 



OX THE INFLUENCE OF INDUSTRIAL OCCUPATIONS ON THE 



EYES. 



The London Society of Arts some time since instituted an inquiry respect- 

 ing the effect of industrial employments on the bodily health of particular 

 organs, and commenced their undertaking with an inquiry into the " indus- 

 trial pathology of trades which affect the eyes." From a lengthened report 

 on this subject to the Society we make the following extracts. Mr. Dixon, 

 surgeon to the Royal Ophthalmic Hospital gives as his opinion that weakness 

 of sight, as a general thing, is owing to over-use of the eyes, and not to any 

 special employment of them, since every day's experience teaches us that the 

 most trying work for the eyes may be followed, provided due moderation is 

 observed. 



Tailors, it is stated are most liable of any class to exhaustion of visual 

 power from over-use of the eyes. Needlewomen and dressmakers come 

 under the same head. It is suggested that needlewomen, embroiderers, etc., 

 should work in rooms hung with green, and having green blinds and curtains 

 to the windows. In China this rule is adopted by the exquisite embroiderers 

 of that country. Needlewomen would also find it greatly to their advantage 

 to change the color of their work as often as possible. The rationale of this 

 is found in the law that variation of stimulus is necessary to preserve the tone 

 and health of any organ of sense, and that prolonged application of the same 

 stimulus exhausts it. 



Injurious consequences to the eyes often result from long continuance of 

 work in the sitting postare. Congestive diseases of theso organs are indi- 

 rectly attributable to this cause, which produces stasis of the circulation, in 

 the abdominal organs, and secondary venous congestion of the choroid coat. 



Among all classes of persons occupied in various ways upon minute ob- 

 jects, instances occur in which the fatigue and distress of the eyes arises not 

 so much from the actual amount of work, as from the patient's attempting to 



