Physiology : A manual for students and practioners / by Theodore C. Guenther and Augustus E. Guenther.

  • Guenther, Theodore C. (Theodore Charles)
Date:
1903
Catalogue details

Licence: Public Domain Mark

Credit: Physiology : A manual for students and practioners / by Theodore C. Guenther and Augustus E. Guenther. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    suhsfaiKTS Ihnt cniistitiiU' tlif looil of aiiimiils, an<l <lurinf^ dijrcs- tioii are cliaiiircd clirmirally l»y iK'iii;,^ l)rou<,'lit into contact willi tlie (lij^e-slive juices. Tlit; active tiiihstaiices iu the latter are coiii- |)lex ori,fanic hoilies tenned enzumrti. They are non-living' suW- stanees eontainiug nitrogen, anil are soluhle in water ami glycer- ine; destroyed hy temperatures from (J0° to 80° C, and inhibited l)v cold and hy the proilucts of their own activity. The (■(kk/u- htt'nni frrmeiifx are an exception to tlie statement that ferments are inhihited hy tlie products of their activity. Tlie most peculiar propi'rtv of all ferments is that in their action they are not u-sed up, .-^o that a small amount of ferment will change an almost in- definite amount of the substance acted upon. They have been .Slid to act by caial)i.'<tx, which means by their mere presence. It is conceivable that a ferment may act through its physical proper- ties or through certain chemical changes that it undergoes, but which leave it ultimately iis it was at tlie beginning. Both possi- bilities may be illustrate<l by phenomena from inorganic nature. For instance, a trace of iodine added to amorphous phosphorus will convert the entire ma.<s into red phosphorus. Tlie iodine un- dergoes no chemical change, but acts through its physical proper- ties, p()s.sibly by inducing a more active molecular vibration iu the phosphorus, so that it assumes a more staple structure. Chittenden hsis given an example illustrating the other pos.sible method of action of enzymes. Carlion monoxide and oxygen, when perfectly drv, cannot be made to unite by means of an electric spark, l)Ut if a small (piantity of water vapor is pre.><ent. they com- bine readily. The following eijuations explain the reactions. In them it is .seen that water takes part in the reaction, but remains finally as it was at the beginning : 2H./) + CO + O, = C0( OH).. + H,0,. H.,0.,+ CO==CO(OH):, 2C0(0H)., = 2C0, + 2H,p. There is much more certainty in regard to the changes proiluce<l in the bodies u])i)n which the enzymes have acted. The.se are in all cases, probalilv, hi/dnillon chaHi/rx—/. r., the substances acted upon take u|) water and then break down into simpler combina- tions. The reasons for this belief are as follows: 1, Enzymes act only in the presence of water.