— 97 — 



it will communicate the disease from the first to the 

 latter. As much care must be used in cleaning it as 

 a surgeon would use in cleansing his instruments after 

 an operation for cancer or gangrene, before again 

 using them upon a healthy person in some other ope- 

 ration. In the " yellows " in peach trees the disease 

 is no doubt mainly communicated through the organs 

 of fertilization, the pollen of the diseased tree coming 

 in contact with the stigma of a healthy one, and com- 

 municating the disease in the same way as syphilis is 

 communicated to a healthy mother through the foetus 

 derived from a father having a syphilitic taint. This 

 disease is so virulent that the roots or branches of a 

 diseased tree coming in contact with the roots or 

 branches of a healthy one will communicate the virus. 



In conducting such experiments as we have sug^ 

 gested, absorption of air and water by the roots and 

 leaves, and also the process of exhalation and respi- 

 ration by the latter, should be studied as a means of 

 detecting the causes of disease and indicating the 

 methods by which remedies may be applied to restore 

 them to health when diseased. 



There is a certainty, at least, of insentient life in 

 plants, if not a close approach in some to sentient life. 



Some forms of it may be chemico-vital action, but 

 others are different and of a higher character. Veget- 

 able physiology and anatomy have received great 

 attention from learned botanists ; their researches 

 have been of much practical service to cultivators^ 



