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no question as to the cleanliness or otherwise of its 

 surroundings ; but not content with giving it abundant 

 — nay, under the circumstances, more than abundant 

 — both fresh and dried insect and vegetable food, he 

 must needs give it preserved egg in addition: against 

 the intensified virulence of the bacilli generated in 

 this delightful material the bird was of course not 

 immune. It was like the majority of negroes when 

 brought to England, and placed under the influence 

 of our indigenous tuberculosis ; and the class of 

 insectivorous birds can be well compared with the 

 civilised European, as regards the effect that a septic 

 diet has upon them both. They can each of them, as 

 a rule, ingest a certain amount of more or less attenu- 

 ated virus of septicaemia without experiencing much 

 harm, but neither of them can withstand even a small 

 dose of the intensified toxin thrown out by vigorous 

 bacilli propagated and nourished under those con- 

 ditions which most favour their progressive develop- 

 ment. Beyond this there is little doubt but that if 

 insectivorous birds were fed on a less nitrogenous diet 

 in captivity than they are, they would fare better and 

 live longer than they do at present. There is as much 

 difference between a Tom-tit at liberty, who has to 

 work hard all day to find his living, and one in a cage 

 or aviary with plent}^ under his nose for the picking 

 up, as there is between the village blacksmith and the 

 mercantile clerk. The blacksmith with unimpaired 

 metabolism can eat to his heart's content without 

 much harm accruing ; feed the sedentary w^orker in 

 the same way and trouble is bound to result from the 

 disproportion between secretion and excretion. And 

 to pursue the analogy a little further : — While the 

 average blacksmith and wild Tom-tit respectively have 

 each of them individually developed sufficient resistive 

 power to enable them to successfully withstand the 

 attacks of infectious germs up to a certain point, the 

 oo well-fed specimens of the captive bird and city 



