Vol. XL No. 260. 



THE AGRICULTURAL NEWS. 



125. 



STUDENTS' CORNER. 



APRIL. 



Second Period. 



Seasonal Notes. 



Explain what is meant by a bud, and state how you 

 would show of what the different parts of a bud consist. 

 What are the uses of leaf buds to plants? State any changes 

 that you have observed in leaf buds, between the time that 

 they become visible and the period at which they expand and 

 eventually form shoots. Where are leaf buds usually found? 

 What is meant by a terminal bud, and what is likely to 

 follow the destruction of such a bud? In regard to dormant 

 buds, how may the presence of these be demonstrated, and 

 how is it sometimes shown that they have existed in a stem? 

 Distinguish between dormant buds and adventitious buds, 

 stating for what reasons the latter may be formed. Adventi- 

 tious buds sometimes develop on roots; give an example 

 where this occurs, and state what advantage may be taken of 

 the circumstance. In what part of the stem, do buds origi- 

 nate, and how may this be shown in a general way? 



How are flower buds distinguished from leaf buds? 

 State, in the case of several plants which you have examined, 

 where the flower buds are generally borne; that is in relation 

 to the age of the wood on which they are found. Give 

 several examples of the use that is made in agriculture of the 

 fact that certain parts of plants possess buds. What is bud 

 variation, and how may it be demonstrated to exist, in the 

 case of any plant with which you are acquainted? 



Under what conditions are flower buds most usually 

 formed? It is sometimes desired to increase the amount of 

 formation of such buds, or to hasten it. In what ways may 

 this be done? It often happens that a' plant produces 

 a large number of buds and flowers while it is still young; 

 what may be the reason for this? 



What signs are shown by plants when the amount of 

 nitrogenous food that they are receiving is in excess? It 

 should be remembered, in regard to the nutrition of plants, 

 that one essential element of food cannot be used instead of 

 another element; if the supply is insufticient in any respect, 

 the plant is dwarfed in all its parts. It may, however, be 

 reduced in size, while there may not be a corresponding 

 lessening in amount of the seed products. This is why 

 plants that are grown for seed or fruit are less likely to show 

 a decrease in yield than those raised for their vegetative parts 

 such as leaves, stems or roots; for instance, it may have been 

 observed often that cotton plants of small size will give 

 a fair yield of seed and lint. It must be remembered, how- 

 ever, that a limit exists in regard to the matter, and that the 

 food-supply may be easily restricted to such an extent as to 

 interfere seriously with the development of all parts of the 

 plant. 



All the above matters should be considered by the 

 student in particular regard to crops of which he has practi- 

 cal knowledge, and with reference to instances that have 

 come, or may come, under his notice. 



Questions for Candidates. 



Preliminary Qukstioss. 



(1) State broadly how roots take up 'plant food from 

 the soil. In what condition must this plant food be, in order 

 that the roots of a plant may make use of it in this way? 



(2) State the chief ways in which - farmyard manure 

 difiers from artificial manure. 



(3) Give a description of any stems that you have 

 examined. 



Intermediate Questions. 



(1) Describe the way in which plant food travels from 

 one part of a soil to another. 



(2) Supply an account of the manner in which any 

 artificial manure, that you have seen, is obtained. 



(3) State the chief differences between the stems of 

 monocotyledons and of dicotyledons, and say what import' 

 these differences possess as regards the agriculturist. 



Final Questions.^ 



(1) State what is meant by Osmosis, and how you 

 would demonstrate its existence in a simple way. 



(2) Write an account of any substance that has been 

 suggested recently to be used as a manurial source of potash. 



(3) Mention as many agricultural products as you can, 

 that are obtained from stems. 



THE USE OF FORMALIN ON RUBBER 



PLANTATIONS. 



An article in the Junrnul d' A'j licuUure Trojncale, for 

 January 1912, p. 1.5, by V. Cayla, refers to a warning that 

 has been given already I)y that journal against the belief by 

 planters that formalin is an anti-coagulant. Formalin actual- 

 ly prevents coagulation only in an indirect manner; it acts 

 as an antiseptic. Through its interference with bacterial 

 activity which would cause acidification of the latex, it 

 indirectly prevents the coagulation of Hevea latex, which is 

 produced in an acid medium. The explanation is necessary, 

 Ijecause it may be alleged that the formalin itself prevents 

 the coagulation of the latex. It is actually a coagulant. At 

 a strength of l-per cent, in water it is inactive as a coagu- 

 lant, and in this proportion it is, if not antiseptic, at least 

 capable of inhibiting bacterial life. 



There is, however, a more complex question concerning 

 formalin which, it is believed, has not so far been considered. 

 The formalin (or formol) of commerce i.s theoretically a solu- 

 tion of formaldehyde at a strength of -tO per cent. When it 

 leaves the manufacturer, it probably answers to this descrip- 

 tion; but the numerous changes that formaldehyde may 

 undergo when it is kept for some time in solution are 

 unknown, and the result is that when the formalin of 

 commerce is being used, one hardly knows the real nature of 

 the substance. It is possible that certain commercial kinds 

 of formalin, at the time that they are being used, do not 

 contain any trace of formaldehyde, but only modifications 

 of that compound. 



In the opinion of the writer of the article, these circum- 

 stances provide the reason for the great discrepancy that 

 exists between the results of dirterent investigators, in 

 experiments in the coagulation of rubber latex by formalin, 

 notably in the work of Chevalier, Christy and Fickendey. 

 Although these experimenters worked under almost the 

 same conditions, the reactions noted by them were different. 

 To summarize the matter, it is the belief of the writer 

 that three points have to be remembered, concerning formalin, 

 in the special connexion: it is a coagulant; it is an antiseptic; 

 and it is a body of which, at the time of its use, one never 

 knows the actual composition, and consequently there is the 

 accompanying ignorance as to its coagulating value. 



