July 10, 1896.] 



SCIENCE. 



31 



health and well being in both man and ani- 

 mals, while the other is deadly to both and 

 also to plants? Certainly the desired in- 

 formation cannot be gained by the chemist's 

 test tube or by application to a dead ani- 

 mal. How are the splendid results of the 

 modern physiological psychology being at- 

 tained? Not by dissecting the dead, but 

 by experimentation upon the living. 



Shall our schools then become the ' cham- 

 bers of horrors ' described f)y the anti- 

 vivisectionists ? Heaven forbid ! The 

 fundamental facts of physiology, those most 

 intelligible and useful for the pnpils in the 

 schools, can be demonstrated for them and 

 by them without the infliction of pain or 

 even discomfort ; and most of them can 

 best be performed by the pupil upon him- 

 self. Let us take a few examples : Every 

 child knows that there is feeling, as he calls 

 it, in the skin ; he also knows the sensation 

 of cold. But he, and indeed most grown 

 people, do not know that the tactile sense 

 does not reside in every part of the skin, 

 and so of the temperature sense. If some 

 object like the rounded end of a lead pencil 

 or a bit of steel be drawn carefully over the 

 skin, say upon the back of the hand, it will 

 be felt simply as an object over the tactile 

 areas, while over the temperature areas 

 there will be a sensation of cold. Then 

 how easy it is to give the real physiology 

 of muscle by having each pupil perform 

 some definite movements of the arms. If 

 the muscles are felt during these move- 

 ments, especially if some force is exerted, 

 as in lifting a weight, the changes in the 

 form and consistency of the muscles can be 

 easily determined. It will also probably be 

 a revelation to the pupil to find that in 

 raiding the arm, for example, the muscles 

 around the shoulder and at the elbow, 

 which by themselves would tend to lower 

 the arm or draw it outward or inward, also 

 contract. After such an experiment it will 

 not be difficult for the pupil to understand 



that, for the steady and definite movements' 

 of parts where the joints give considerable 

 freedom, it is necessary that there should 

 also be a moderate contraction of antagon- 

 istic or opposing muscles which by them- 

 selves would cause movements in other direc- 

 tions ; that is, he will gain, by such a simple 

 experiment, the ground idea of coordination. 



Perhaps none of the experiments that 

 can be performed are of more practical util- 

 ity than some simple ones in digestion. It 

 is now very easy to obtain from the phar- 

 macies the ferment of the stomach or of the 

 pancreas. With these ferments and a glass 

 vessel the pupils can see for themselves the 

 solvent action on various forms of food. 

 They can see that finely divided food is 

 more quickly dissolved than large masses, 

 and hence one of the principal advantages 

 of thorough mastication. So if the ferment 

 of the saliva or pancreas were mixed with 

 raw starch and with cooked starch it could be 

 seen, with a distinctness never to be forgot- 

 ten, that fire is a powerful ally of the hu- 

 man digestive organs. These experiments 

 are also instructive because the processes 

 are practically identical with those going 

 on in the living body, and thus . illustrate 

 the side of physiology that may be demon- 

 strated without experimenting on a living 

 organism. 



The circulation of the blood is a fact of 

 such fundamental importance and so inter- 

 esting in itself that every student ought to 

 have the privilege of viewing it under a 

 microscope. This can be very easily shown 

 in the web of a frog's foot or in the external 

 gills of a water salamander like the Nec- 

 turus. If a little ether is put in the water 

 containing the animal it will soon become 

 ansesthetized without interfering with the 

 circulation. The ether will render the per- 

 fectly painless observation successful with- 

 out even arousing the apprehensions of the 

 animal, which soon revives when placed 

 again in fresh water, and appears as happy 



