18 



♦ KNOWLEDGE ♦ 



fJDLY 13, 1883. 



each portion must concur with the rest, just as much as the 

 several joints do in a preliensile monkey's tail. Many 

 infusoria have a plurality of whips at their anterior end. 

 Fig. 4, AmpMinonas dispar, has two; Fig. 3, Cercomonas 

 acuminata, has one at each end, and it must want some 

 skill to prevent their motions from conflicting. 



Fig. 6 represents Euplotes patella in two positions. The 

 under side is exhibited in a, and h gives a profile view. 

 This creature swims with its cilia, or walks with its bristles. 

 Intelligence, or a sufficient substitute for it, guides the 

 animal to the right use of these two sets of organs, but 

 nothing in the locomotive line done by the ciliata, or hetero- 

 tricha, is so wonderful as the Etujlena whip work. 



Fig. 1 (a) 



Kg. 1 (6). 



Fig. 2 (a). 



Fig. 2 (6). 



Fig. 3. 



Fig. 4. Fig. 5. Fig. 6 (a). Fig. 6 (b). 



Fig. 1, a and 6, represents the spores and young of Heteromita 

 lens, X 800. Fig. 2, a and h, Euglena viridis in two positions, 

 X 250. Fig. 3, Cercomonas acuminata, x 500. Fig. 4, Amphi- 

 monas dispar, x 300. Fig. 5, Paramecium aurelia, x 75. Fig. G, 

 Eaptotes patella, «, underside; li, walking attitude, x 140. 



When any bird or insect does a skilful-looking thing, it 

 is popularly said to be directed by iKsliitc/, but few persons 

 endeavour to mean anything really intelligible by the term. 

 Instinct in birds and insects, for example, is not, as often 

 asserted, unerring ; it does not compel the creature always 

 to do the same thing. It does not preclude experiment, 

 and, to a certain extent, a modification of plan and use of 

 new materials. Instincts are probably inherited aptitudes, 

 and in their higher exhibition are associated with 

 reason. What are we to say of the lower and of 

 the far minuter objects that perform acts of locomo- 

 tion, food-seeking, itc, in a way that must be called 

 skilful, and which would be impossible unless their bit 

 of protoplasm had molecules so arranged as to perform 

 work analogous in character to the nerve actions of higher 

 animals 1 They must receive impulses from without, and 

 send forth the right sort of impulses in reply to them. 

 To avoid an obstacle means taking some physical cogni- 

 sance of it, and directing the motile organs accordingly. 

 To move after prey witli aspect of skill requires some 

 faculty of recognising where it is, of distinguishing it 

 from other things, and of steering accordingly. Do these 



minute creatures think ? No one supposes that they are 

 conscious of their existence ; that they reflect upon the 

 sense impulses they receive ; or that they knowingly exer- 

 cise a will force, or have such a feeling as desire ; but, 

 after dismissing as improbable the attributes that belong to 

 animals with an elaborate nervous organisation, there is 

 much to be accounted for that differentiates them very 

 strongly from inorganic matter, and that prefigures some, 

 at least, of the mental processes of higher beings. 



In investigating the phenomena of living beings we soon 

 feel that we are in the presence of an unknown something 

 which is not like any merely physical or mechanical force. 



The iodine solution may be made by dissolving on"^ 

 grain of iodine and three of iodide of potassium in one 

 ounce of distilled water. Half the quantity is an abundant 

 stock for the numerous experiments for which iodine is. 

 useful. 



CHEMISTRY OF THE CEREALS. 



By William Jago, F.C.S. 



No. I. 



THE name " Cereals " is applied to the group of grasse.s 

 cultivated for human food ; included in their number 

 arc wheat, barley, rye, oats, maize, and rice. As a result 

 of analysis we find these bodies to consist in great part of 

 organic compounds, together with a small proportion of 

 inorganic material. This latter, derived from the soil on 

 which the plant has grown, contains potassium phosphate- 

 magnesia, lime, silica, and minute quantities of other in- 

 gredients. Our present purpose leads us more especially 

 to the study of the organic constituents of the members 

 of the great grain family ; these bodies are themselves of 

 inestimable value to man, and further, by virtue of certaiii 

 chemical changes, yield a number of other most useful and 

 interesting products. Subjoined is a table giving thi- 

 average composition of the cereal grains : — 



Wheat. Barley. Oats. Eve. ilaize. Rice. 



Water Ill 120 142 143 llo lOS 



Starch 623 52-7 56-1 549 548 788 



Fat 1-2 2-6 4-6 20 47 01 



Cellulose 83 11-5 10 G-4 149 Oi 



Gum and Sugar... 38 4-2 57 11-3 2-9 re- 

 Albuminoids 10-9 13-2 IGO 8-8 8-9 7-2 



Mineral matter ... I'G 28 2-2 1-8 1-6 0-J> 



Loss, Ac 0-8 10 0-2 Oo 07 0-4 



1000 1000 1000 1000 lOOO lOO-O 



We see from this table that water is present to a greater 

 or less extent in all, wheat and rice containing the least 

 quantity. The sample of wheat was, however, an old one, 

 and therefore will have got drier by keeping. 



We also see that starch is by far the most abundant 

 constituent of these grains ; its percentage ranges from 

 ,52 '7 in barley to 788 in rice. The first step, then, in thf- 

 study of the chemistry of the cereals will be to make our- 

 selves acquainted with the nature and properties of thii 

 body. The composition of starch is represented by tht- 

 formula C,-H]|,0-,. Its general appearance is well known, 

 for, besides being largely used for laundry purposes, we 

 find it occurring in a considerable number of other pre- 

 parations ; thus "violet powder" is, or should be, pure 

 starch, scented with orris root, and the various "corn- 

 Hours " are simply the starch of maize. Let us take a 

 sample of starch as sold by the chemist and e.xamine it. 

 We have a fine white powder, which, on being pressec'i 

 between the fingers, produces a peculiar sound, known as 

 "crepitating." An examination under the microscope 

 shows that this powder possesses a very marked struc- 



