Conservative. 25 ounces. Do neb apply any logic to this evidence ; my brain may weigh 88 ounces , and another man's may weigh 04 , without his mental capacity being equal to mine. The extent of the so- called "gray" matter , how ever , as indicated by the number and complexity of the convolutions , maybe bo a partial index to the mental capa city of the individual. In considering brain-weight , the body-weight should always bo taken into account. The process by which man has at tained his position in the zoological scale has not boon duo to physical strength , for lie has conquered animals possessing a far greater strength. His supremacy in the struggle or exist ence has been duo to the superiority of his brain development. Man possesses many structures of no possible present use , which cannot be explained upon any basis , except that of descent from lower forms of life , where they were of value. I have often referred in other articles to the rudimentary muscles for moving the cars , and the muscles in the skin , which , in the lower auimls , servo to erect the hair , but which , in man , have no other function than to cause the "gooseflesh" of fear or cold. The pineal gland is , in all probabil ity , the remnant of a third eye , at times distinguishable , though not operative , in the young of the New Zealand reptile , the sphenodon. This gland was formerly regarded by ortho dox people as the seat of the soul. The vermiform appendix , which many surgeons so clearly love to remove , is a remnant of a herbivorous ancestor which required a large-sized caecum for. the necessary retardation of a too rapid process of digestion. The use of the pitutary body , which is at the base of the nose , is still a mystery. It is true , of course , that wo cannot produce the complete palaeoutological history of the human animal , as we can the history of the crocodiles , the rhinoceroses and the horses , partly because - cause palaeontology is a comparatively new science , partly because no thor ough search has been systematically made perhaps because the land of man's ancestors is now under the sea. We have , however , such evidence as the Neanderthal man , found in Prus sia , about 1857 , and the Pithecanthro pus Erectus , found in Java about five years ago. The former appears to have been a cave-dweller , and his skull differs from that of any known man. The latter ought to satisfy the imagin ation of those who speculate concern ing a ' ' missing link. ' ' Some interest ing pictures of the skull have appeared in a popular magazine. Ono may assert that all the evidence of palaeontology , of zoology , of com parative anatomy and embryology is unimportant , because the true distino- \ tion between mankind and the other animals is to bo found in the region of mind and morals. Now , as to the absence of language among the lower forms of life of course Darwin saw this difficulty what is language , I ask. It is the com munication of thought , feeling , ideas generally to others by means of artic ulate sounds. Can wo bo sure that the lower animals are not possessed of language in this sense ? I trow not. Upon the other hand a very little ob servation will convince anybody that many animals , not only can , but do convoy to their comrades their feel ings and desires. And ho , indeed , will bo a bold man who is prepared to deny that the numerous sounds emitted by animals play no part in this convey ance. Is there , I ask , a greater gap be tween the language used by such ani mals and the few harsh sounds em ployed by the lowest savages , than be tween the language of the lowest human beings and the elaborate speech of a highly educated American or European ? The sounds emitted by dogs or horses may seem few , but it is well to remember that , instead of trying to learn what these animals know , we use all our energy in trying to teach them what we know. The natural question is , where does sound end and speech begin ? Who is pre pared to draw the line ? I venture to assert that the differences are a mere matter of degree. In the face of our ignorance upon this subject and the small amount of attention that has been paid to it , it is well to bo very circumspect. That organs anatomical , such as the vocal organs of men and apes , should bo functionally different is , to my mind , most improbable. The ac tion of our vocal apparatus is depend ent upon our organ of breathing , and the manipulation of respiration is partially dependent upon the position of the body. The development of our particular mode of speech may bo corelativo of the erect position so char acteristic of man. The development of language is merely one phase of the much larger question of the mental distinctions be tween man and the rest of the animal world , and I venture to assert that the law of the survival of the fittest is an abundant explanation of mental eve lution. Do not lot us allow any dust to bo thrown in our eyes. This ques tion docs not involve the mental cone dition of highly civilized human beings - ings ; it is merely a question of the mental differences between the high est animals , below man , and the least civilized human beings. \ Everybody knows that the lowest animals are not destitute of intelli gence. In Darwin's Descent of Man , are to be found many well-authenti- cated facts showing that the same emotions and characteristics , such as curiosity , imitation , memory , atten tion and oven reason , are observed in some animals , beside man. The love of a dog for his owner is proverbial ; maternal affection is ' strikingly de veloped in many beasts. Monkeys are successful as performers , in consequence quence of their powers of attention and imitation. Ants unquestionably possess memory ; and if dogs and cats do not dream , my observation must bo very much , * at fault. Darwin has recounted some extraordinary cases of the reasoning of retriever clogs ; and my experience convinces mo that the dogma that man is the only reasoner cannot bo supported by any scientific evidence. There is but one way in which all these facts can bo interpreted viz : by concluding that in all the so-called "higher" mental attributes the true difference between man and the lower animals is , to quote from the prince of observers , Sir John Lubbock , "one of degree and not of kind. ' ' Darwin's of the explanation psycho logical side of evolution essentially consists of the application of his prin ciple of natural selection. Let me re mark that , prior to his time , psychol ogy was a more mass of verbosity and metaphysical peudautry ; it was not a science at all , and apart from physiol ogy it is not now , and never can be a science. Darwin's discussion of in stinct in the Origin of Species , and the light ho was able to throw upon ob scure cases by the aid of natural selec tionformed a suitable commencement to true psychological science. In the Descent of Man , he deals with the mental characteristics of man and of other animals in a masterly manner. Congenital mental variation favorable to its possessor is very often transmit ted to the next generation ; and the con tinued survival of the fittest from a mental point of view must cause a gradual development of ' the mental faculties. All you need to do is to satisfy yourself that the process of natural selection is the truth , and then the solution of the problem is simple. The origin of language , and of all the higher faculties , including reason , is the result of congenital mental variation , the survival of those best suited to the ] environment , and the transmission of such congenital characteristics as are of benefit to the individual in the strv-gglo for life. "I cannot doubt , " writes Darwin , "that language owes its origin to the imita tion and modification of various natur al sounds , the voices of the animals and man's own instinctive cries , aided and . ' ' by signs gestures. In concluding this very brief sketch , I wish to give Darwin's answer to those who are shocked at the idea of / " ' " > . . . < f S.'i