234 



SCIENCE. 



nutritive material was bought at 44 cents per pound. The 

 cost of the nutritive material in one sample of halibut was 

 57 cents, and in the other $1.45 per pound, though both 

 were purchased in the same place at the same price — 15 

 cents per pound, gross weight. In closing, Professor At- 

 water referred to the widespread but unfounded notion that 

 fish is particularly valuable for brain food on account of its 

 large content of phosphorus. Suffice it to say that there is 

 no evidence as yet to prove that the flesh of fish is specially 

 richer in phosphorus than other meats are, and that, even 

 if it were so, there is no proof that it would be on that ac- 

 count more valuable for brain food. The question of the 

 nourishment of the brain and the sources of intellectual 

 energy are too abstruse for speedy solution in the present 

 condition of our knowledge. 



ANATOMY OF THE TONGUE IN SNAKES AND 

 OTHER REPTILES, AND IN BIRDS.* 



By Dr. C. S. Minot. 



The tongue arises as a protuberance on the floor of the 

 mouth, which in the course of development acquires a mus- 

 cular system ; the latter appears first in the reptiles. The 

 principal muscles are the longitudinal arising from the hyoid 

 bones, morphologically a part of the branchial muscles. In 

 the crocodiles these are the only muscles found. In the 

 snakes, however, proper lingual muscles play an important 

 part, there being a distinct vertical muscle between the 

 Ceratoglossi, three distinct transverse muscles, one superior 

 and two inferior, and finally a longitudinal muscle immedi- 

 ately under the upper surface of the free portion of the 

 tongue. Each muscle is distinct and separate throughout 

 its whole course; they can all be traced with facility. The 

 disposition of the nerves and other parts of the tongue was 

 also described. The examination of the tongue of an Ameiva, 

 the common long-tail lizard, revealed a structure in all its 

 features identical with that of the snake's tongue. This 

 offers a confirmation of the view that lizards and snakes are 

 closely related, for in no other class of reptiles has a snake- 

 like tongue been observed. On the other hand, the tongue 

 of the Chamseleon is peculiar. It has been previously 

 studied by several authors, all of whom have committed 

 important errors. The whole tongue is exceedingly com- 

 plicated and difficult to understand. The arrangement of 

 the muscles is the most remarkable yet observed among 

 animals, and they cannot be homologized with the muscles of 

 the tongue of any other animal, until our knowledge of the 

 subject shall be greatly enlarged. Dr. Minot stated, while 

 he had made new observations on the tongue of the cha- 

 maeleon, that he had been led to recognize more clearly, 

 than previous writers, the difficulty of explaining the me- 

 chanism of the organ. The tongue of birds presents a uni- 

 form type, distinct from that of any reptile. The tongue 

 has its simplest and lowest form in the crocodiles, is much 

 advanced in the snake and fissilingual lizards, remarkably 

 transformed in the chamreleon, and presents a special type 

 in birds. These points are brought out by numerous mi- 

 croscopical observations on the nerves, blood vessels and 

 other parts. 



SOME FACTS AND THEORIES BEARING A 

 RELATION TO THE DISTRIBUTION OF 

 ORGANIC FORMS ON THE GLOBE.t 

 By W. H. Davis. 



The author commenced by pointing out the fact that the 

 inorganic conditions which surround us arc in a state of 

 change, ceaseless, and ever varying ; and illustrated tin's 

 portion of the subject by references to denudation and re- 

 deposition of exisiing land surfaces. It was then shown 

 that these inorganic changes could not take place without 

 at the same time producing an effect on the organic world 

 commensurate in some degree with the intensity of the inor- 

 ganic change ; this led up to the question of the same area 

 of the earth's Blirface at successive periods possessing a 

 varying fauna and Bora, and the light thrown by pabconto- 



logical investigation upon the changes of land surface that 



♦ Read before the A. A. A. S., Hoston, 1880. 



t Read before the Metropolitan Scientific Association, London, 

 England, Oct. 12, 1880. 



had taken place, and this knowledge of past conditions in 

 its turn throwing an instructive light upon the former range 

 of the various orders and genera of organic beings. Thus 

 it was, that as there was a perpetual ebb and flow and cease- 

 less interchange of inorganic structure, so the forms and 

 types of life pffected by these influences are also in a con- 

 tinual and corresponding state of unrest, from the nec- 

 essity of the two conditions being in harmony with each 

 other, the organic and the inorganic. 



The first problem, therefore, was, seeing that a change of 

 the organism was necessitated by a variation in the condi- 

 tions of existence, whether these changed conditions as they 

 arise were of themselves capable of inducing structural 

 differences in organized forms subjected to their influences. 

 Starting with the negative view, it was pointed out that 

 there were but two courses open to the organism affected — 

 migration or extinction ; but the former cause of itself in- 

 volved a minor change of conditions, and as in the life his- 

 tory of the earth, a second, third, or greater number of 

 migrations were necessitated, at last the probabilities were 

 of the environment of the organism being so varied from 

 its primary condition that extinction in this case must also 

 ensue. Thus a form persisting through several or many 

 periods of geological time would be impossible ; but as 

 this was contrary to many observed facts, the converse 

 view was discussed, and actual structural modifications due 

 to changed conditions referred to, as in the case of animals 

 and plants introduced into West Africa, South America, 

 and other regions. Mimicry was also instanced as evidence 

 of the influence of inorganic form on living organisms. 

 In man the Europeo-American nation of the United States 

 was quoted as an instance of a race being formed under 

 our very eyes. 



It may, of course, be urged that the differences here 

 pointed out are only of a character such as might be 

 anticipated to have arisen, and that, pendulum-like, they 

 vibrate through a very small arc, and in no way give rise to 

 fresh species, still less to fresh genera. The next point, 

 therefore, that comes in for consideration is whether these 

 structural differences are ever commutative. We have seen 

 that the change which can be produced in a single species 

 is not an alteration in respect of one character only, but 

 an alteration of many characters affecting different parts 

 and portions of the same organism. Now these modifica- 

 tions, small as they are (in comparison with the question of 

 a complete change of species), certainly did not leap into 

 being in an instant, but have exhibited themselves grad- 

 ually. Here, then, is a starting-point for the cumulative 

 evidence. The changes themselves, even so far as they 

 have gone at present, are but expressed cumulative results, 

 and having become once established, it is only in accord- 

 ance with what we have already seen to be the case, that 

 with a further change of surroundings, a corresponding 

 modification must ensue, or extinction alone must follow. 

 But in this argument we are not altogether left to the evi- 

 dence as visible to the eyes of mankind during the historic 

 period, but a mass of the facts of palajontological history, 

 some embryological investigations, and many zoological 

 observations are absolutely inexplicable save on these 

 grounds. If we trace the connections of the reptilian and 

 avian forms, the progressive stages in time of the Equidrc, 

 or the changes in structure of the more lowly Ammonitidrc, 

 the same answers must be given, that the extremes observed 

 in the respective groups have been the result of a cumula- 

 tive modification due to the types of life being in a condi- 

 tion of instability, and ever seeking to bring themselves into 

 harmony with tlieir inorganic surroundings. 



In further illustration of this portion of the subject, sym- 

 pathetic modification or correlative adaptation may be noted, 

 as when the change of one structure in an animal induces 

 changes in other structures remote and apparently uncon- 

 nected with it, as in the pigeon, the beak and toe lengthen- 

 ing and shortening in unison. 



Degeneration was strongly insisted upon as a factor in 

 producing fresh types, equally with progressive modifi- 

 cation. 



Passing, then, to the various views entertained as to the 



causes of the present geographical distribution of life, the 



doctrine of specific centres was explained, the author main- 

 taining that this idea was, in effect, but the old ideological 

 argument that every organism was created for a definite 



