about the composition of any body whatever, as it is. Tlie state- 

 ment that a crystal of calc-spar consists of carbonate of lime, is 

 quite true, if we only mean tliat, by appropriate processes, it may 

 be resolved into carbonic acid and quicklime. If you pass the 

 same carbonic acid over the very quicklime tlnis obtained, you 

 will obtain carbonate of lime again ; but it will not be calc-spar, 

 nor anything like it. Can it, therefore, be said that cliemical 

 analysis teaches nothing about the chemical composition of calc- 

 spar ? Such a statement would be absurd; but is is hardlv 

 more so than the talk one occasionally hears about tlie uselessness 

 of applying the results of chemical analysis to the living bodies 

 which have yielded them. One fact, at any rate, is out of reach 

 of such refinements, and this is, that all the forms of protoplasm 

 which have yet been examined contain the four elements, carbon, 

 hydrogen, oxygen, and nitrogen, in very complex union," and 

 that they behave similarly towards several reagents. To this 

 complex combination, the nature of which has never been deter- 

 mined Tvith exactness, the name of Protein lias been appliec!. 

 And if we use this term with such caution as may properly arise 

 out of our comparative ignorance of the things for which it stands, 

 it may be truly said, that all protoplasm is proteinaceous ; or, as 

 the white, or albumen, of an egg is one of the commonest exam- 

 ples of a nearly pure proteine matter, we may say that all living 

 matter is more or less albuminoid. Perhaps it would not yet l>e 

 safe to say that all forms of j)rotoplasm are affected by the direct 

 action of electric shocks ; and yet the number of cases in whicli 

 the contraction of protoplasm sliown to be effected by this agency 

 increases every day. Nor can it be affirmed with perfect confi- 

 dence that all forms of protoplasm are liable to uiidergo that pecu- 

 liar coagulation at the temperature of 40 degrees — 50 degrees 

 centigrade,which has been called "heat-stiffening," though Ktlhue''s 

 beautiful rescarclies have |»roved this occurrence to take place in 

 so many and such diverse living beings, that it is hardly rash to 

 expect that the law holds good for all. Enough has, perhaps, 

 been said to prove the existence of a general uniformity in tlu^ 

 character of the protoplasm, or physical basis of life, in whatever 

 group of living beings it may be studied. But it will be under- 

 Btood that this general iiniformity by no means excludes any 

 amount of special modifications of the fundamental substance. 

 The mineral, carbonate of lime, assumes an immense diversity of 

 characters, though no one doubts that under all these Protean 

 changes it is one and the same thing. 



