Febeuaey 10, 1899.] 



SCmNGE. 



207 



itself, giving 7.662 water-meters, or about 

 25 feet of water-pressure. 



For any other solute than sugar we have 

 only to substitute its molecular weight for 

 the denomination 342 in the above work. 

 Substituting 2 for it, for hydrogen, the re- 

 sult is 1153 water-meters, a forcible token 

 of its livelj' difl'usibility. 



The Freezing-Point. — Though this has no 

 connection with physiologj', the lowering of 

 the freezing-point in solution is cited by 

 Starling as a step towards finding osmotic- 

 pressure, which we have seen to be de- 

 terminable in a less troublesome way. We 

 give the converse case ; having found the 

 pressure, to ascertain by its aid the freez- 

 ing point of a 1 p. c. solution of cane- 

 sugar. 



The law of thermodynamics gives this 

 proportion : 



Work done _ 

 Heat during it 



Lowering (A) of Total Heat 

 Total Heat. 



In this case the work done is 6.748 water- 

 meters-pressure (as was found above). The 

 heat doing it is the latent part of water, 

 79.9 calories per gram, which is reduced to 

 water-meters-pressure by multiplying by 

 427. 



The total heat is the absolute tempera- 

 ture at 0°C.; this is 273. Thus the propor- 

 tion becomes 



6.748 _ A 

 427 (79.9) ~ 273", 



giving A = 0°.054C. This result is substan- 

 tially identical with that cited by Starling 

 fromvan't Hoff, and signifies that the par- 

 ticular solution of sugar in water lowers 

 the freezing-point more than one-twentieth 

 of a degree. If the solution had repre- 

 sented a gram-molecule of sugar in a liter 

 of water the depression of the freezing- 

 point would be nearly 2°C., a constant 

 well-known to physicists. 



Writers on physiology usually state that 

 processes of absorption within the body are 

 more rapid than can be fully explained by 

 experiments on diffusion. A partial ex- 

 planation of this peculiarity will, I think, 

 be found in the fact that experiments are 

 made on dead and comparatively rigid 

 membranes, and the living membranes of 

 the body are almost fluid in their soft- 

 ness. Whether osmosis be by a transitory 

 combination or by passing through tem- 

 porary pores, it involves in the living body a 

 minimum of friction. We know how much 

 more rapidly blood can pass through flexi- 

 ble, living vessels than through rigid tubes. 



(I am indebted to my colleague Professor 

 E. H. Loomis for advice.) 



Geoege Macloskie. 

 Princeton" Univeesity. 

 January 5, 1899. 



PROFESSIONAL SCHOOLS VS. BUSINESS. 



An exceedingly interesting and instruc- 

 tive experiment has been in progress dur- 

 ing the last few years at Sibley College, 

 Cornell University, the outcome of which 

 will perhaps have peculiar interest for all 

 who are concerned with education and pro- 

 fessional training, the data of which experi- 

 ment are exhibited in the accompanj'ing 

 diagram, showing the growth in numbers 

 of that college from its date of reorganiza- 

 tion as a professional school, in 1885, to the 

 present time. The diagram is taken from 

 the paper read before the Association of 

 Promotion of Engineering Education, at 

 the Boston meeting of 1898, by the writer. 



Up to the year 1885 Sibley College was 

 without expert direction, a definite policy, 

 a settled curriculum or a systematically 

 organized facultj'. It had been established 

 as a ' school of the mechanic arts ' for 

 many years, but had not graduated a hun- 

 dred students in its whole career. In 1885 

 the Trustees of the University found them- 

 selves in a position to undertake the work 



