OKLAHOMA ACADEMY OF SCIENCE 55 



rapidly expanding. The field of general physiology is indeed a 

 rich one and from it are being gained conceptions of the most fun- 

 damental character. 



The last field of endeavor to be mentioned here is a very new 

 one indeed. It has long been known that certain organs of the 

 body produce substances that are discharged into the blood stream 

 directly and are known as internal secretions or hormones. It 

 is now realized that the production of hormones is much more 

 common than had formerly been dreamed, and their study is the 

 object of the newest member of the biological family, Endocrinol- 

 ogy. A'though the endocrine organs do not constitute a system 

 in the ordinary sense of the term organ system, they are a source 

 of chemical control of body process that is of the most far 

 reaching importance. Certain hormones are secreted by organs 

 which have no other functions than their production, while others 

 are the results of the activity of special cells imbedded in such 

 organs as the pancreas and i"he reproductive organs, of which physi- 

 ologically they form no part. Still other hormones are without 

 doubt produced and utilized within the body of single cells. One 

 of the common examples of the hormones is the thyroid gland, the 

 general effect of which is to regulate the rate of oxidation in the 

 body. As an examp'c of the nicety of control and adjustment 

 within an organism which depends upon production of hormones, 

 "it may be mentioned that the thyroid gland itself is subject to regu- 

 lating stimiuli reaching it through the nervous system as well as 

 by a hormone derived from, the pituitary body which is another 

 endocrine gland situated in conjunction with the lower part of 

 the brain," (Woodruff). Investigations of hormones and their 

 part in influencing the activities of the body are now affording 

 insights into mechanisms which in many cases were not even su- 

 spected. 



If from a consideration of these chief lines of ir.s activity 

 one were to attempt to characterize in a word the modern zoologi- 

 cal point of view, he might say that it is an attempt to apply the 

 experimental method to the animial kingdom and the re-interpret 

 vital phenomina in the terms of the new knowledge thus gained. A.i 

 illustration of this tendency and at the same time a prediction of 

 future problems for the investigator is the growing fie'.d of experi- 

 mental ecology ; that is, the relations of an organism to its environ- 

 ments, and the experimental study of the causes and effects, which 

 underlie these relationships and adaptations. While descriptive 

 and speculative zoology represent mere'.y stages in the progress of 

 the science when viewed from the experimental standpoint, they 



