\ he-e nitrogenous substances. Tin- germs, seeds, and those parts by 

 which cells multiply themselves abound in nitrogenous substances; the 

 --tun total of the phenomena \\hidi are proper to organisms depend, 

 before all. on the chemical properties of the nitrogenous substances 

 which enter into their eoinposit ion. It is enough, tor instance, t o point 

 out the fact that vegetable and animal organisms, dearly distinguish- 

 able as such, are characterised by a dilierent degree of energy in their 

 nature, and at the same time by a difference in the amount of nitro- 

 genous substances they contain. In plants, which compared with 

 animals possess but little activity, being incapable of independent move- 

 ment, iVc.. the amount of nitrogenous substances is very much less than 

 in animals, who-e tissues are almost exclusively formed of nitrogenous 

 substances. It is remarkable that the nitrogenous parts of plants, 

 chietlv of the lower orders, sometimes present both iorms and properties 

 which approach to those of animal organisms : tor example, the xoo- 

 spores of seaweeds, or those parts by means of which the latter multiply 

 themselves. These xoospores on leaving the seaweed in many respects 

 re-einble the lower orders of animal life, having, like the latter, the pro- 

 perty of moving. They also approach the animal kingdom in their com- 

 jio.-ition, their outer coat containing nitrogenous matter. IMrectlv the 

 xoospore becomes covered with that non-nitrogenous or cellular coating 

 which is proper to all the o'-dinarv cells of plants, it loses all re- 

 semblance to an animal organism and becomes a small plant. 1 1 may be 

 thought from this that the cause of the diH'erence in the vital processes 

 of animals and plants is the different amount of nitrogenous substances 

 'hey contain. Tho-e nitrogenous elements which occur in plants and 

 animals apperta in to the series of exceedingly coin] 'lex and very change- 

 able chemical compounds: their elementary composition alone shows 

 this; besides nitrogen, they contain carbon, hydrogen, oxygen, and 

 -ulphur. I'eing distinguished by a very great instability under many 

 condition-; in uhidi other compounds remain unchanged, these sub- 

 -tance.- are titled for those perpetual changes which form the first con- 

 dition of \ii;il activity. These complex and changeable nitrogenous 

 , lances of the or^ani-m are called jir<>t<'nl unhxtn uri-n. The white 

 (if egg- is a familiar example of such a substance. They are also 

 contained in the lle-h of animals, the curdy dements of milk, the 

 glutinous matter of \\heaten Hour, or so called gluten, \\hidi forms the 

 diicf component < if macan >ni. ive. 



Ni'r'>L f en occur- in the earth crust, in compounds either forming 

 the remain- of pl:i ni - ;i i id a nimals, or derived t rom the n 1 1 rogen ot the 

 atmosphere as a con-djuence of it.- combination with the other com- 

 ponent pan- of the air. It \-^ not found in other forms in the earths 



