SCIENCE. 



117 



ized beings. Graham, in 1862, drew the sharp line 

 which separates colloid from crystalloid matter. " His 

 researches have required," says Maudsley, " a change 

 in our conception of solid matter. Instead of the no- 

 tion of inert impenetrable matter, we must substitute the 

 idea of matter which in its colloidal state is penetrable, 

 exhibits energy, and is widely susceptible to external 

 agents. This sort of energy is not a result of chemical ac- 

 tion, for colloids are singularly inert in all ordinary chem- 

 ical relations, but is a result of its unknown molecular 

 constitution ; and the undoubted existence of colloidal 

 energy in organic substances, which are usually considered 

 inert and called dead, may well warrant the belief of its 

 larger and more essential operation in organic matter in 

 the state of instability of composition in which it is when 

 under the condition ot life. Such energy would then suf- 

 fice to account for the simple uniform movements of the 

 homogeneous substance of which the lowest animal con- 

 sists, and the absence of any differentiation of structure is 

 a sufficient reason for the absence of any localization of 

 any function and of the general uniform reaction to local 

 impressions." Graham himself says: "the colloidal state 

 may be looked upon as the probable primary source of the 

 force appearing in the phenomena of vitality." The col- 

 loidal condition of the dynamical state of matter ; the crys- 

 talloida! the static. The former, which is the rule in the 

 organic kingdom of nature, is the exception in the inor- 

 ganic. Aluminum and ferric hydrates, silicic acid and a 

 few other inorganic substances, exist in the colloid condi- 

 tion. From analogy there would seem to be but little 

 doubt that the colloid state of these bodies differ from their 

 crystalloid state merely in the size of the molecule. In 

 other words opal, which is colloid silica, is a polymer of 

 quartz. If this theory be true there can be no doubt of the 

 vastly greater complexity of a colloidal proteid molecule 

 than of a crystalloid one. Now it is a very significant fact, 

 in this connection, that not a single organic colloid has 

 ever been synthesized. Gelatin, which is one of the best 

 examples of a colloid, has a comparatively simple structure. 

 And, although Gibbs showed, many years ago, that gelatin 

 was probably an amido-derivative of the sugar group, yet 

 no inverse process has yet given us this substance. That 

 matter in the crystalloid and colloid forms may be chemi- 

 cally identical, differing only in the size of its molecule, 

 may be quite possible. But it is also possible that the dif- 

 ference may be a physical one. To produce the colloid 

 state from the crystalloid is by no means beyond the power 

 of science. We qualify our previous statement then only 

 so far as to say that when the chemist produces a body in 

 the colloidal form, having the identical constitution of pro- 

 toplasm, there is every reason to believe that it will have 

 the properties of protoplasm. 



The important question now arises whether, since the 

 protoplasm of animals is identical with that of vegetables, 

 and the latter is the food of the former, any protoplasm 

 whatever is vitalized by the animal as such. That this iden- 

 tity exists would seem satisfactorily established. Though 

 the protoplasm of vegetables is enclosed within a cellulose 

 bag, it is only a closely imprisoned rhizopod. In the Ni- 

 tella, it shows all its characteristic irritability, and from 

 Vaucheria it escapes to exhibit all its amoeboid movements. 

 Spores swim about by cilia or flagella, and the cell division 

 of the one kingdom is the same as that of the other. In 

 plants, however, protoplasm seems to be associated with 

 chlorophyll, whose function was for a long time supposed 

 to be to decompose carbon dioxide under the influence of 

 sunlight. But Draper in 1843, showed that this decomposi- 

 tion took place before the chlorophyll was formed. Recent 

 researches have shown that the function of chlorophyll is 

 wholly protective. The assimilative power of the proto- 

 plasm reaches its maximum in the orange and yellow rays. 

 Now Bert has shown that the absorption band in the chlor- 

 ophyll spectrum is in the exact position of this maximum. 

 Hence, Gautier believes that this substance acts as a regu- 

 lator of plant respiration, the greater or less amount of lu- 

 minous energy thus absorbed and transformed, being util- 

 ized by the protoplasm and stored up. Growth and cell- 

 division, however, are independent of orange light, and 

 hence of chlorophyll. In the higher plants, these functions 

 are performed by a separate and deep-lying set of cells. 

 But in the lower, the same cell discharges both functions, 



assimilation going on in it during the day. and growth 

 chiefly at night, Sachs had already proved that the maxi- 

 mum growth of plants takes place just before daylight and 

 the minimum in the afternoon. This retarding action of 

 sunlight upon growth is as curious as it is unexpected. It 

 now appears that in orange light plants assimilate — absorb 

 carbon dioxide and evolve oxygen — but do not grow — are 

 not heliotropic ; while in blue light they are heliotropic but 

 do not give off oxygen. Chlorophyll, however, is not con- 

 fined to vegetables ; infusoria, hydras, and certain planarian 

 worms are green from the presence of this substance, and 

 Geddes has shown that such animals, placed in the sunlight, 

 give off a gas which is more than half oxygen. These cells, 

 moreover, contain starch granules. 



A still more striking evidence of this intimate relationship 

 has been developed by Darwin, in his researches upon in- 

 sectivorous plants. Not only do these plants possess a me- 

 chanism for capturing insects, but they secrete a gastric 

 juice which digests them. Nageli has shown the presence 

 of pepsin in yeast cells, and attention has lately been called 

 by Wurtz and others to the juice of the Carica papaya which 

 contains a pepsin-like substance capable of peptonizing fibrin 

 completely. Moreover, there is the closest similarity be- 

 tween diastase and ptyalin ; and the milk of the cow-tree, 

 recently examined by Boussingault and found to resemble 

 cream closely in composition, shows the presence of an 

 emulsifying agent in the vegetable kingdom analogous to 

 pancreatin in the animal. 



Another most curious proof of the indentity of animal and 

 vegetable protoplasm has been given by Claude Bernard, 

 who has shown that both are alike sensitive to the influence 

 of anaesthetics. A sensitive plant exposed to ether no longer 

 closed its leaflets when touched. Assimilation and growth, 

 as well as germination, are arrested by chloroform. The 

 yeast plant when etherized no longer decomposes sugar to 

 produce alcohol and carbon dioxide ; while the inversive 

 and non-vital ferment still acts to convert the cane-sugar into 

 glucose ; precisely as under these circumstances, the dias- 

 tasic ferment converts the starch of the seed into sugar. 

 By arresting anaesthetically the process by which carbon 

 dioxide is absorbed and oxygen evolved, the true respira- 

 tory process, being less effected, now appears ; and Schut- 

 zenberger has proved that the fresh cells of the yeast plan 

 breathe like an aquatic animal. 



It would seem then that the protoplasmic life of animals 

 is identical with that of plants ; a certain measure of destruc- 

 tive metamorphosis taking place in each, evolving energy 

 and producing carbon-dioxide and water. When, however, 

 this function is examined quantitatively, its maximum is 

 seen to be reached in the animal. While the assimilative 

 function characterizes the plant, the destructive function 

 distinguishes the animal. Hence it is the function of the 

 plant to store up energy, to produce the highly ccmplex 

 protoplasm. This, consumed by the animal as his food, 

 continues his existence as a living being, the energy gradu- 

 ally set free by its successive steps of retrogressive meta- 

 morphosis, appearing as the work which he performs. If 

 this view be correct, it would follow that every individual 

 substance found in the animal — save only those which re- 

 sult from degredation — must be found in the plant upon 

 which it feeds, and this is the fact. The myosin which 

 Kuhne has shown to be the distinctive proteid of muscle, 

 Vines has found in the aleuron grains of the lupine and the 

 castor oil plant, along with vitellini the special proteid of 

 the vitellus. The researches of Weyl & Bischoffhave proved 

 that gluten is formed in the dough of wheat flour by the ac- 

 tion of a ferment upon the globulin-substance or plant-myo- 

 sin which it contains, precisely as Hammarsten has shown 

 fibrin is produced in the action of a similar ferment upon 

 fibrinogen. Not only this ; Hoppe Seyler has extracted 

 from maize the identical substance which has been shown 

 by Liebriech to be the essential chemical constituent of nerve 

 tissue, protagon. 



The evidence then would seem conclusive that, since the 

 protoplasm of the animal and the vegetable kingdoms is 

 identical, the former in all cases being derived from the 

 latter, the animal as such neither produces nor vitalizes any 

 protoplasm. Two inferences seem naturally to follow from 

 this conclusion : 1st, that all the properties of animal proto- 

 plasm, and of the animal organism of which it constitutes 

 the essential part, must have a previous existence in the 



