1877.] 



AND HORTICULTURIST. 



95 



him to be present, he informed me that he could 

 not attend the meeting, and that he would pre- 

 fer the report should be delayed for another 

 year, as some gentlemen in his section of the 

 State had promised to investigate the matter 

 n(3xt season, and it was presumed that the com- 

 mittee of the Am. Society would also report at 

 that time. I therefore consented to defer mak- 

 ing a report, especially as I did not believe that 

 the public^would lose much by the delay. In 

 saying this, however, I. did not wish to be under- 

 stood as intimating that there was nothing in the 

 supposed discovery of Mr. McCall — for in my 

 opinion the commencement of' the blight may 

 be often traced to the injury or cause assigned by 

 him ; but in a majority of cases no such cause 

 can be discovered, at least in Northern Ohio> 

 where my observations have been made. 



I next called attention to the remarks of Mr. 

 Meehan, of the Gardener's Monthly, at the last 

 meeting of the Am. Pom. Soc, (see report of 

 proceedings,) "on Fungi and Fruit Diseases," in 

 which he says, " That fire blight is of fungoid 

 origin, is now clear, from the researches of Dr. J. 

 Gibbons Hunt of Philadelphia. He finds that a 

 very minute fungus germinates on the outer 

 bark, enters the structure, destroying the cells as 

 it goes, till it reaches the alburnum, and then it 

 penetrates clear to the pith, by way of the me- 

 dullary rays, totally destroying the branch, from 

 the centre to the circumference. . . There is 

 no other conclusion here than that reached by 

 Dr. H., that, in the true fire blight, fungi are the 

 cause of the disease." 



I remarked that, accepting this conclusion as 

 we must, the honor of first demonstrating its cor- 

 rectness belongs to a skilled mycologist of our 

 own state. Dr. J. H. Salisbury, now of Cleve- 

 land, whose researches on this subject, made in 

 1862, are published, with numerous illustrations, 

 in the Ohio Agricultural Report for 1863. Un- 

 fortunately the wood-cuts illustrating the essay 

 of Dr. H., were accidentally burned some years 

 since, or our Society would have the substance 

 of it republished. In examining the blighted 

 branches with a powerful microscope, Dr. S. 

 found them filled through and through with the 

 mycelium of a peculiar fungus; the threads 

 wound around in every direction among the 

 woody cells. For several inches beyond the 

 outward appearance of disease, dead lines, the 

 size of a knitting needle, extended in the soft 

 cambium, and in these the moniliform threads 

 could be traced making their way among the 



cells. This plant. Dr. S. saj^s, is strictly a para- 

 sitic fungus that affects organic tissues. It pro- 

 duces blight in twig of apple and quince, as 

 well as pear, and often attacks the young fruit 

 when about the size of a hazel-nut. This fungus 

 belongs to the group Ascomycetes, to the order 

 Perenosporiaceffi, and the genus Sphserotheca. 

 The method of development of the fungus is fully 

 illustrated by Dr. S. The fertile threads grow 

 by pullulation (like bud-forming) ; the spores 

 are produced on threads that rise above the sur- 

 face. Sporidia and fertile threads were placed 

 in a solution of sugar, and the next day numer- 

 ous zoosporoid cells were moving about actively, 

 and in a little time some of them voided other 

 cells, all the while continuing a pvilsating or 

 vibratory motion. 



Another and distinct form of fungus was ob- 

 served and described by Dr. S., as found in the 

 blighted branches after they had been dead some 

 time, and along with the one causing the dis- 

 ease ; but this second kind does not prey upon 

 living tissue, and is a result, not a cause of dis- 

 ease. Dr. S. supposes that the sporidia of the 

 blight fungus are in the circulating juices or sap 

 of the tree, and under favoring influences of the 

 weather, and a suitable condition of the cam- 

 bium, are started into growth. He sviggests, in 

 the line of preventives, the use of sulphur in 

 some of its soluble forms applied to the soil 

 about the roots. But as some experiments of 

 this kind have not been wholly satisfactory, and 

 it is probable that the spores enter by the sto- 

 mata of the leaves, or else vegetate on the out- 

 side of the bark, and then pass inward, it is sug- 

 gested that washes containing sulphur, carbolic 

 acid, or copperas be applied to the trees by 

 syringing, early in Summer. Let us hear 

 Mr. Saunders, of Washington, 'and others who 

 have tried such washes, as to the extent and 

 manner of their doing it, and the results. It is 

 my belief that a reliable and cheap preventive 

 will be found only in this direction. 



PROF. BRAINERD ON SOLAR HEAT THEORY. 



We also had, at our meeting, the somewhat 

 remarkable essay on pear blight, read before the 

 Potomac Fruit Growers' Association last Sep- 

 tember, by Prof. J. Brainerd, formerly of Cleve- 

 land, and now of the Patent Office at Washing- 

 ton, published, with illustrations, in the Ohio 

 Agricultural Report for 1875-6. The Committee 

 of our Society were of the same opinion respect- 



