28 



SCIENCE. 



universally, and form part of the education of every 

 liberal-minded and intelligent man. Dr. Draper's 

 books show that he was a deep thinker in the depart- 

 ment of the philosophy of history and human progress, 

 and that he aimed to exalt the intellectual develop- 

 ment of man. 



The " History of the Conflict of Religion and Sci- 

 ence" a work which many readers consider is incor- 

 rectly represented by the title, proves how broad and 

 liberal were Dr. Draper's views, and it may surprise 

 many to learn, that such opinions were net considered 

 by him inconsistent with religious belief. The material- 

 ists appear to have written and published in vain for 

 him, as we are told in the " American Journal of Sci- 

 ence'' that " it is a satisfaction to affirm that he 

 was a theist and a firm believer in a future state of ex- 

 istence, for which the present is only a preparation." 



On the 4th of January last, Dr. Draper peacefully 

 surrendered his life, honored and respected by all na- 

 tions, for his fame had been diffused throughout the 

 civilized world by reason of the translation of his 

 works into both European and Asiatic languages. 



Dr. Draper leaves two daughters and three sons, 

 the latter having already achieved distinction in pur- 

 suits kindred to the work of their father. As the work 

 of Herschell was continued by his son, so in Professor 

 Henry Draper we find all the special qualities for 

 maintaining the high prestige of the family name ; his 

 recent success in photographing such difficult celestial 

 objects as nebulous matter, and the important discov- 

 ery of the presence of oxygen in the sun, have placed 

 him in the foremost rank of original scientific work- 

 ers, and the furthur development of his investigations 

 are anticipated with keen interest by physicists, both 

 in this country and abroad. 



VEGETABLE PATHOLOGY. 

 By T. J. BURRILL, Ph. D. 



It is not an easy accomplishment to separate physiology 

 from pathology when, instead of dealing with the defini- 

 tions of words, we attempt to classify the operations 

 taking place within a living object, by placing them in the 

 one or the other category of activities and effects. In- 

 deed there is no well marked and uniformly acceptable 

 line of division. We may speak of one as normal and 

 healthful and the other as abnormal and injurious ; but 

 these vary with the standpoint from which our judgment 

 is made, and with the conditions which modify, this way 

 and that, the results. 



If these things are true as regards the vital processes of 

 animals, they are much more evidently true concerning 

 those of plants. In the latter, the standards of health 

 and disease are not so well agreed upon ; less attention 

 has been given to the life processes and their results ; the 



individuality of the plant has been less recognized, and 

 its own particular good or injury less regarded. If an 

 apple-tree produces for us a crop of good sized, highly 

 flavored, richly colored fruit, we do not stop to ask 

 whether these luscious pippins are the results of physiolo- 

 gical or pathological operations, judged from the stand- 

 point of the tree. If a cabbage has its terminal bud 

 enormously developed so as to be called a head, the 

 monstrosity never calls forth a compassionate word of 

 sympathy as we enjoy the crisp and savory production, 

 for a New Year's dinner. The ink with which we pre- 

 serve our thoughts, flows no less freely because of a pecu- 

 liar wound in a particular tree by a particular insect, and 

 a most wonderful malformation of the growing tissues in 

 consequence. We have not listened to the masterly dis- 

 quisition of a learned and betitled oak upon septicemia 

 or the curiosities of traumatic tumors. We have heard 

 no complaints from suffering, bleeding grape vines ; no 

 uneasy groans from plants perishing through the wither- 

 ing effects of blight and mildew. 



But the terms physiology and pathology do have a 

 meaning answering to the operations and conditions of 

 health and disease in plants as well as in animals. The 

 grasses of the fields and meadows may flourish in the 

 luxuriance of bountiful supply and perfect adaption, their 

 vital forces being attuned and harmonized into combina- 

 tions of causes and consequences, all conspiring to the 

 good of the individual and the welfare of the species ; or 

 these members of the vegetable kingdom, may, through 

 unfavorable conditions, through privation, through the 

 attack of enemies, become dwarfed or distorted, weak or 

 disproportioned, unfruitful or incapable of growth and 

 self-perpetuation. 



Without attempting to give in this place a classification 

 of the diseases of plants, much less a description of the 

 many that are now known and more or less clearly under- 

 stood as to origin and progress, we proceed to give some 

 account of a few of the more general facts and pheno- 

 mena connected with our subject. 



THE PROCESSES OF PHYSIOLOGY AND PATHOLOGY IN 

 PLANTS ARE SLOW. 



Except in the case of violently disturbing causes, like 

 fire, frost, caustic chemicals, etc., disease or death never 

 attacks a plant in the sudden and unheralded manner 

 frequently known in animals. It is true that what has 

 been called "blight," a very indefinite and loosely applied 

 term, is usually supposed to be the work of a day or a 

 night, perhaps of an hour; but the facts have not been 

 known by those who make this supposition. If by 

 " blight " is meant the results of a tornado or even of a 

 sirocco, with which we of Illinois can claim some ac- 

 quaintance after the last summer's experience — if these 

 are meant, we cannot say that "blight "is not sudden; 

 but the effects of such agencies should be classed as in- 

 juries rather than as diseases, There are really no ex- 

 ceptions to the rule that true pathological operations in 

 plants are slow in their progress. The healing of wounds 

 offers us a good illustration, if we examine the process in 

 plants compared with that in animals. If from a healthy, 

 rapidly growing tree, we cut off a limb close to the trunk, 

 making a wound one inch in diameter, a whole year will 

 scarcely suffice for complete healing, while in most ani» 

 mals a clean cut of this kind may be covered with newly 

 produced tissue in a fortnight. We talk about the circu- 

 lation of the sap ; but in plants the fluids do not circu- 

 late in any proper sense. The slow movement which 

 does take place is at best a process of soaking. When 

 water is most rapidly ascending in the stem of a leafy 

 plant to supply the loss by transpiration, one foot per 

 hour is more than is commonly gained ; and this is 

 altogether exceptional speed for movements in plants 

 generally. This feeble distribution of the fluids in living 

 vegetation is no doubt one of the reasons for the slow 

 workings of disease. Again the want of sympathetic 



