iiUl 



NATURAL SCIENCE: 



A Monthly Review of Scientific Progress. 



No. 29. Vol. V. JULY 1894. 



NOTES AND COMMENTS. 



Mathematical Biology. 



IN one of his delightful " Imaginary Portraits," Mr. Walter Pater 

 gives a rendering of the mediaeval legend of the return of the 

 golden age, as a pagan Renaissance caused by the actual return 

 among men of a denizen of ancient Greece. There came, under the 

 influence of the reborn pagan, a period strangely in dissonance with 

 the times before and after. " One man engaged with another in talk 

 in the market-place; a new influence came forth at the contact. 

 Another and then another adhered. At last a new spirit was abroad 

 everywhere. The hot nights were noisy with swarming troops of 

 dishevelled women and youths with red-stained limbs and faces, 

 carrying their lighted torches over the vine-clad hills, or rushing down 

 the streets, to the horror of timid watchers, towards the cool spaces 

 by the river. A shrill music, a laughter at all things, was everywhere." 

 It is not the kind of pagan to cause these occurrences who has been 

 born among us. But the prevailing application of physical reasoning 

 to Biology, so often referred to in Natural Science, might be 

 pictured under the idea that someone who, with Democritus, had sat 

 at the feet of Leucipptis, had been working in the German laboratories 

 and had been, indoctrinating Oxford and Cambridge and London. 

 Professor Weismann's germ-plasm in its later elaborate form is a 

 notable instance of the new tendency. In it the whole organism is 

 formed of units of different grades. The unit of each higher grade 

 is a multiple of the unit of the grade next lower. The multiples of 

 each unit are built up in some physical scheme of architectonics. 

 Biitschli refers the structure of protoplasm and its physical properties 

 to questions of density and surface tension. In many parts of his 

 argument one must have a text-book of physics open to understand 

 him. A large part of the current work upon variation is expressed in 

 mathematical terms, while the study of growth almost necessarily 

 involves mathematical reasoning. 



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