98 report — 1865. 



property of the ovum per se, or of tb.3 nutrient plasma by which that ovum is 

 nourished up to the time of its birth ? Could food, or mode of life, or any specific 

 agent eradicate the tendencies to transmission, just as in certain cases we empi- 

 rically modify the transmission of tubercle ? or is the transmission of the Carcinoma 

 as inevitable in certain cases as the development of the germ ? Grave questions for 

 future solution. 



These allusions to disease, I need not say, are purposely introduced. There 

 Bvduis to be a tendency in some modern physiologists to pay insufficient attention 

 to the retrograde metamorphosis of living creatures. The study of death is as 

 much an object of biological science as the study of birth. The whole being 

 originates, reaches maturity, declines, and dies. So does every part. He strives 

 with vain endeavour to grasp the history of any organic thing, who does not 

 regard it in relation to its origin, its growth, its dissolution, its relations to 

 objects external to it, the changes which it undergoes in itself and of itself, an 1 

 the modifications, accidental or necessary, which external agents can and may in- 

 duce in it. 



General considerations of this kind have a certain, though subordinate office in 

 scientific deliberations, and seem just now not out of place. It will be remembered 

 that I have been speaking of the intrinsic difficulties of biological study. If I have 

 correctly, though briefly, sketched the domain of Biology, the existence of these 

 difficulties will be conceded. They are now insisted upon, not certainly so much 

 for the sake of those skilled experts, our teachers, who are carrying on the con- 

 quest of Nature, as of those many cultivated learners who, from want of leisure, 

 cannot actively pursue, but who, from real interest, desire to aid and promote 

 the study of Biology. For them it is desirable to take from time to time a general 

 survey of the aims and extent of Biology, in order that they may bring the weight 

 of their influence in support — 1st, of free, unfettered pursuit of Biology for its 

 own sake ; and 2ndly, of public education, such as may conduce in the next gene- 

 ration to a just appreciation of its scientific, its educational, and its practical value. 

 I am thus led to consider, 2ndly, the Prejudices of Mankind, " opiniones 

 prcejudicatce," in respect of Biology. 



These resolve themselves into Active Prejudices and Passive Prejudices. Active 

 lead men to object to it as harmful; Passive lead them to regard it with in- 

 difference. 



These prejudices are rapidly undergoing modification, but they have existed harm- 

 fully more or less, from various causes, among almost all but professed Physiologists. 

 I need only advert among the Active prejudices to the so-called theological dread of 

 free inquiry into the origin of Paces, and the origin of Species generally. Among 

 the Passive prejudices, I would point to the want of appreciation of purely scientific 

 inquiry that has no practical end in view ; to objections of various kinds brought 

 against experiments made for Physiological, Toxicological or Therapeutical pur- 

 poses ; to objections to the introduction of Biological studies into courses of general 

 education ; to the tardy recognition of Biological knowledge as the basis of practical 

 Medicine, and of Hygiene, public and private. 



History gives the clue to the source of these prejudices, namely, the empirical 

 assumptions of supposed truths made at former, and often ancient epochs, which 

 have one by one to be eradicated from their respective departments before the 

 advancing knowledge of ascertained Natural Law. 



What we see around us in the natural world is admitted on all sides to be the 

 result of the operations of causes working by fixed laws. Why those laws exist, or 

 how they came to be, it is not within the domain of Physical Science to discuss. 

 What (in so far as they affect living beings) they are, and what the mode and limit 

 of their action, including (of course) the mode and limits of their possible modifi- 

 cation, is the special province of Biological Science. Science therefore is not only 

 at liberty, but is bound, at all times to test the correctness of opinions which bear 

 on or have relations to the subject matter of science, and do not appear to have been 

 founded on adequate scientific evidence. A great part of the scientific work in the 

 present century has been that of recasting or rejecting received dogmas. This work 

 is not yet complete, .and possibly never will be. It is evident that new means of 

 research show the incorrectness of the belief of many of the greatest minds. Plato 



