FOREWORD TO TEACHERS 17 



of every educated person's equipment in life. These factors are 

 strongly emphasized in the working out of the problems of this 

 book. 



An attempt has been made by the author to be practical as well 

 as logical, and to gain interest through the practical treatment of 

 things that are famihar to the pupil. Whenever possible, techni- 

 cal terms are done away with, and experiments are made as simple 

 as possible without destroying their scientific value. 



In general, a few large group problems have been made that 

 directly explain the text of the author's Civic Biology, which this 

 manual is intended to interpret in the laboratory. In addition to 

 these, other secondary but closely associated problems are added 

 with less explicit directions, so as to give opportunity for some 

 mental activity in their solution on the part of the pupil. It is 

 not expected that all the problems are to be attempted in a year's 

 course in elementary biology, but a choice should be made by the 

 instructor of what he considers the most important for his own 

 particular classes. 



The author wishes especially to thank Messrs. George T. Hastings, 

 John W. Teitz, and Frank M. Wheat of the Department of Biology 

 in the De Witt Clinton High School for their many helpful sug- 

 gestions and for certain of the exercises and excellent drawings 

 accompanying many of the experiments. All members of the 

 department have in one way or another given ideas to the lab- 

 oratory exercises which follow, and my sincere personal thanks 

 are due to them as well. 



The author also wishes to make acknowledgment to the various 

 sources from which the experiments and laboratory exercises of 

 the following pages were adapted. Of especial value in this 

 respect have been the numerous publications of the Department 

 of Agriculture, the Bureau of Fisheries, and the various health 

 reports of state and city Boards of Health. The Cornell Uni- 

 versity Reading Course Pamphlets and their Nature Study 

 Leaflets have also been of much service, especially in the work on 

 dietetics. In the laboratory study of dietaries the 100 Calorie 

 Portion Table of Irving Fisher, compiled from the Journal of the 

 American Medical Association, Vol. XLVIII, No. 16, has also 



HUNTER LAB. PROB. 2 



