30 KANSAS l/NIVERSITY SCIENCE BULLETIN. 



stimulated the different centers, and if there were ions that 

 simulated one but proved neutral or inhibitory to the other 

 centers. Moreover, whether valency or solution tension were 

 influential factors, and if the toxicity produced on either the 

 respiratory, cardiac or vasomotor centers by certain salts could 

 be counteracted by definite amounts of other salts that proved 

 antitoxic. Before I had proceeded far, however, I desired, in 

 addition to the solution of some of these questions, to study 

 other physical and chemical effects that were produced in the 

 body by the salts ; e. g., osmotic pressure, the products of chem- 

 ical reactions, such as oxygen, carbon dioxide, hydrogen and 

 hydroxyl ions, and the dosage of the solutions. 



I realize that in experiments of this character a host of phe- 

 nomena may exert their influence and that it is difficult with 

 the data at hand to assign to any special one the cause that 

 produces the particular result. Some of the events which may 

 deserve consideration can, however, be controlled and their in- 

 fluence either accounted for or removed from further consid- 

 eration. That is especially so in the investigation of the fishes, 

 where the temperature and supply of the water can be con- 

 trolled and are kept normal and constant throughout the ex- 

 periment and where the amount of solution injected bears a 

 direct proportion to the weight of the animal, and also where 

 from the method employed mechanical stimulation, either due 

 to the insertion of the cannula or brought about by retaining 

 the fish in a definite position during the experiment, is avoided. 



On the other hand, we assume that the addition of an isotonic 

 salt solution to the blood, the chosen amount of which does not 

 cause any change in any of the functions under consideration, 

 will, if hypo- or hyper-tonic, produce various physical and 

 chemical alterations both in the fluids and tissues of the body. 

 Introducing an additional salt into the blood assumes changes 

 in its osmotic pressure and in the contents of the corpuscles, 

 also alterations in the permeability of the walls of the capilla- 

 ries, corpuscles and other tissue cells. Or the new composition 

 in blood salts may make new combinations with colloids or 

 ferments or proferments, or set free ions that will thus stimu- 

 late or inhibit functions by acting directly on cardiac or muscle 

 cells, or indirectly upon special centers. That is, the physio- 

 logical property of the blood is altered by changing the propor- 

 tion and character of the electroljrtes in it, and this must have 



