330 PROCEEDINGS OP THE ACADEMY OP [1886. 



We turn from these slight hints to the record of an experiment 

 in inoculation, made in 1845 and published the following year. 

 We are told by S. B. Gookins/ of Indiana, that visiting Mr. 

 Ragan (the same person who furnished Mr. Beecher with many 

 of the facts on which he founded the theory to which we have 

 already referred) he was shown a thrift}' young pear-tree in the 

 nurser}', which had been " inoculated " " by way of experiment " 

 with " the sap of a blighted tree," " a few days previous." " He 

 made an incision about three feet from the ground, lifted the 

 bark as in the process of budding, and injected a small quantity 

 of the diseased sap." " We found the leaves of the patient chang- 

 ing color, and emitting that peculiar odor which is always present 

 in cases of blight, and upon appl3'ing the knife, the inner bark 

 was found to be black from the root to the top, while nothing of 

 the kind appeared elsewhere in the nursery." 



This admirable experiment was combined with a no less admir- 

 able interpretation of the cause of blight. The writer cites facts 

 to disprove the hypothesis of Mr. Beecher, and then says : " I 

 strongly incline to the belief, that the pear-blight is an epidemic, 

 that it prevails like other epidemics, and will pass off like them. 

 The atmosphere is, I believe, generally admitted to be the medium 

 by which they prevail, and are carried from place to place. What 

 that subtle principle may be, which pervades our atmosphere, by 

 which infection is retained and transmitted, human science has 

 not discovered ; but that such a principle exists is sufficiently 

 obvious from its effects." 



This clearly conceived elucidation of the matter could onlj' 

 have been improved by a knowledge of the germ theory of disease, 

 and when we remember the date at which it was uttered, we do 

 not feel that the writer was guilty of any lack of acuteness in not 

 perceiving the relation which we now know to exist between his 

 theory and his facts. He seems to have been a modest man, for 

 he only signs his initials, and does not defend his views when the 

 editor, A. J. Downing,^ opposes the opinion that " an epidemic 

 conveyed by the atmosphere is too slightly supported by facts to 

 weigh at all against the observations of cultivators," which 

 " strongly point to the freezing of the sap as the cause." 



' Horticulturist, vol. i, 1846, p. 253. 

 ' Horticulturist, vol. i, 1846, p. 255. 



