THE CANADIAN HORTICULTURIST. 



one of each pair was sprayed, and the 

 other left unsprayed as a check plant. 

 The six pair were then divided into 

 three lots of two pairs each for treat- 

 ment with Bordeaux mixture of different 

 compositions. 



Unsprayed Sprayed 

 No9. Nog 



1 



2 (pear)) o^-,™^ (4* lbs. cop.sulph. 

 't Snroyeaj 2 11,3 linje, 

 3 4 (pear)j *"" ( 40 gals, of water 



6(peach)|3^^^^|4ims.cop^su.ph. 



7 8 (qu'ce)J ^^^^ ( 40 gals, water. 



9 10 (P^>-)1 Spr.ayed/*i,},^^«-;'PP,«"'P'^- 



11 12 (pear)/ "^^^ \vi gals, of water. 



A small atomizer, such as is used for 

 throat troubles, was used, in order to 

 ensure an even wetting of the surfaces 

 of the leaves. Four successive applica- 

 tions were made on February loth, i6th, 

 23rd, and March the ist respectively. 



On March the loth, specimens of 

 leaves corresponding in size, age, and 

 position on the stem, were taken and 

 put through the process of imbedding in 

 parafifin, in order that sections of exactly 

 the same thickness might be made of 

 them. The plants were afterwards 

 sprayed on March i6th, 24th, and April 

 5th ; leaves were again selected in the 

 same manner and imbedded by the 

 same methods. 



Transverse sections across the central 

 part of the leaf were cut with a micro- 

 tome ; so that the sections were of the 

 same thickness. No noticeable changes 

 were observed in the foliage of the plants, 

 until the time of the fifth application, 

 when two and four which had been 

 treated with the mixture containing the 

 small amount of lime, appeared some- 

 what crumpled, but did not turn black. 

 A critical examination and comparison 

 of all the plants after the last spraying, 

 revealed a marked difference between 

 the color of the sprayed and the un 

 sprayed plants. Those treated with an 

 excess of lime mixture were decidedly 

 greener than the unsprayed ones, while 



those treated with the neutralized or 

 second mixture also showed a deeper 

 green, though not so marked as in the 

 previous case. A microscopic examina- 

 tion of the leaves of Nos. two and four, 

 which were treated with the unneutral- 

 ized solution, failed to distinguish any 

 gain in the amount of chlorophyll in the 

 cells. So this experiment seemed to 

 prove that the increased greenness of the 

 foliage was in direct ratio to the quantity 

 of lime used ; and an examination of 

 the sections of the leaves bore out the 

 observations made on the external ap- 

 pearance. The most noticeable feature 

 was the increase in the number of chlor- 

 ophyll granules, both in the palisade 

 cells and in the spongy parenchyma of 

 the sprayed leaves. Thus the increase 

 was in proportion to the amount of lime 

 used. 



The chlorophyll of the sprayed leaves 

 was also a brighter green than that of 

 the unsprayed. 



In many places the treated leaves 

 showed a third layer of palisade cells 

 more or less continuous ; in the un- 

 treated leaves, nothing more than a few 

 scattered palisade cells were seen in ad- 

 dition to the usual double layer. 



Measurements of the thickness of the 

 leaves were made by means of the mi- 

 crometer, from six to twelve of each leaf 

 having been taken. The results in aver- 

 ages were as follows : 



No. 1 (plum) unap'ed, 141 mic'tres ) diff'ence =4 2inm8 



No. 4 (plum) spr'ed 136.8 " ilossfr 8p'ing=2.3% 



No. 3 (pear) unsp'ed 177.6 " ) difl'ence=4.2 mms 



No. 4 (pear) sprayed 181.8 " j" g'n f r 8p'ing=2.3% 



No. 5 (peach) unsp'd 123 " ) diflference=9 mme 



No. C (peach) spr'ed 132 " ) g'n fr 8p'ing=7.3% 



No. 7 (quince)un8'ed 169.3 " ) diflE'ence=l.l mms 



No. 8 (quince)8p'ed 168.1 " Jg'n fr 8pr'ing=16% 



No. 9 (pear) unsp'ed 162.1 " ) diff'ence=12.1mms 



No.lO(pear) sprayed 174.2 " j g'n fr 8pr'ing=7.5% 



No.ll (pear) unsp'ed 168.2 " ) difference=18 mms 



N0.I2 (pear)9prayed 186.2 " f g'n fr 8p'ing=10.7% 



It might be explained that in the case 

 of the quince. No. 7 was a much more 

 vigorous plant than No. 8. 



While the wide variations shown are 



100 



