NATURAL SCIENCE NEWS. 



for if Nature chose, she could af- 

 ford there to build her inhabitants 

 on three times the scale she does 

 on earth, without their ever find- 

 ing it out except by interplanetary 

 comparison. 



As we all know, a very large 

 man is much more unwieldly than 

 a very small one. An elephant re- 

 fuses to hop like a flea; not be- 

 cause he considers it undignified 

 to do so. but simply because he 

 cannot take the step. If we could, 

 we should all jump straight across 

 the street, instead of painfully pad- 

 dling through the mud. Our in- 

 ability to do so depends partly on 

 the size of the earth, and partly on 

 the size of our own bodies, but not 

 at all on what it at first seems en- 

 tirely to depend on, the size of the 

 street. 



To see this, let us consider the 

 very simplest case, that of stand- 

 ing erect. To this every-day feat 

 opposes itself the weight of the 

 body simply, a thing of three di- 

 mensions, height, breadth and 

 thickness, while the ability to ac- 

 complish it resides in the cross- 

 section of the muscles of the knee, 

 a thing of only two dimensions, 

 breadth and thickness. Conse- 

 quently, a person half as large 

 again as another has about twice 

 the supporting capacity of that 

 other, but about three times as 

 much to support. Standing there- 

 fore tires him out more quickly. 

 If his size were to go on increasing 

 he would at last reach a stature at 

 which he would no longer be able 

 to stand at all, but would have to 

 lie down. You shall see the same 

 effect in quite inanimate objects. 

 Take two cylinders of parafnne 

 wax, one made into an ordinary 

 candle, the other into a gigantic 

 facsimile of one, and then stand 

 both upon their bases. To the 

 small one nothing happens. The 

 big one, however, begins to settle, 

 the base actually made viscous by 

 the pressure of the weight above. 



Now apply -this principle to a 

 possible inhabitant of Mars, and 

 suppose him to be constructed 

 three times as large as a human 

 being in every dimension. If he 

 were on earth, he would weigh 

 twenty-seven times as much as the 

 human being, but on the surface 

 of Mars, since gravity there is only 

 about one-third of what it is here, 

 he would weigh but nine times as 

 much. The cross-section of his 

 muscles would be nine times as 

 great. Therefore the ratio of his 

 supporting power to the weight he 

 must support would be the same 

 as ours. Consequently; he would 



be able to stand with no more fa- 

 tigue than we experience. Now 

 consider the work he might be 

 able to do. His muscles, having 

 length, breadth and thickness, 

 would all be twenty-seven times as 

 effective as ours. He would prove 

 twenty-seven times as strong as 

 we, and could accomplish twenty- 

 seven times as much. But he 

 would further work upon what re- 

 quired, owing to decreased grav- 

 ity, but one-third the effort to 

 overcome. His effective force, 

 therefore, would be eighty-one 

 times as great as man's, whether 

 in digging canals or in other bod- 

 ily occupation. As gravity on the 

 surface of Mars is really a little 

 more than one-third that at the 

 surface of the earth, the true ratio 

 is not eighty-one but about fifty; 

 that is, a Martian would be phys- 

 ically, fifty-fold more efficient than 

 a man. 



As the reader will observe, there 

 is nothing problematical about 

 this deduction whatever. It ex- 

 presses an abstract ratio of physi- 

 cal capabilities which much exist 

 between the two planets, quite ir- 

 respective of whether there be 

 denizens on either, or how other 

 conditions may further affect their 

 forms. 



Animal Biology in High Schools 

 and Colleges. 



No one at the present day, 

 questions the importance of ani- 

 mal biology in the curriculum of 

 all well conducted high schools 

 and colleges as well as in the bet- 

 ter endowed universities and pro- 

 fessional schools. ' The question is 

 rather, how may this be accom- 

 plished? That there is a sad lack 

 of competent instruction in these 

 branches, even in schools that 

 make it their business to educate 

 teachers, cannot be denied. 



The need is only too apparent 

 but the laboratory method is not 

 the way to remedy the defect in 

 our smaller colleges and high 

 schools, because it is beyond their 

 financial ability to secure it. 



This obstacle may, however, be 

 overcome to a certain extent by 

 the use of the stereopticon and 

 lantern slides which may be had 

 at a cost that is within the reach 

 of any school board. The price 

 of stereopticons has, within the 

 past few years, been materially re- 

 duced and the quality greatly im- 

 proved, so that now a good work- 

 ing lantern with suitable acces. 

 sories for projecting photo-micro 



graphs on the screen, for ordin; 

 class work, may be had for a si 

 as low as fifty dollars. Then ag; 

 the process of reproducing histol< 

 ical subjects has of late been so ( 

 veloped that they may be had fn 

 almost all dealers in school si 

 plies at a nominal outlay. V< 

 little has, however, been writt 

 upon this method of illustrati 

 lectures on physiology and 1 

 giene in our public schools and 

 is with this in view that I have 1 

 dertaken the present article. 



I have no hesitancy in saying, 

 the outset, that a better und 

 stauding of the histology of ; 

 sues can be imparted to a grea 

 number of students in a gi\ 

 space of time by this means tf 

 can be obtained by the laborotc 

 method. I do not desire to 

 understood as decrying the pra, 

 cal working laboratory. Wh> 

 time and equipment are sufHci 

 no better method can be had 

 studying biology in all its phas 

 but where either of the above 

 sentials is lacking the lantern 1 

 comes a valuable substitute, e 

 even where the laboratory metl 

 is employed I have found the 1 

 tern a very valuable adjunct in 

 parting a general knowledge 

 the subject. As a method of 

 lustrating didactic lectures on 1 

 tology I consider it far ahead 

 charts. In its use the mattei 

 "personal equation" is reduced 

 the minimum, and it carries 

 more vivid impression of the oi 

 inal tissue because of the fact t 

 it is a photograph. In the use 

 the lantern the educated sen 

 are appealed to and valuable ti 

 saved that in the laboratory me 

 od is spent in learning the te 

 nique of the microscope which 

 after years is of little avail unl 

 the individual continues in prai 

 cal laboratory work. If the < 

 ject sought is the making of i 

 croscopists and original investig 

 ors then use the laboratory me 

 od combined with the lantern 

 class demonstration, but if time 

 equipment is a desideratum J 

 lantern will be found tobefu! 

 adequate for good class instr 

 tion. Ten years' experience as 

 teacher of biology leads me 

 speak thus positively on this qu> 

 tion. Trained in the best Germ; 

 laboratories I naturally follow i 

 their methods when I began teai | 

 ing. Gradually the lantern vi 

 introduced to illustrate didacj 

 lectures. At first, use was mal 

 of the oxyhydrogen lime light 

 projecting actual tissues upon 1 1 

 screen. Many valuable specinKl 



