These variations within each of the vertebrate classes would seem to call for special anatomic-physiologic studies; studies on differences in blood supply of the two gonads in genera differing in the above respect, and a much more definite knowledge of the relative size of the two testes in these groups, being particularly desirable. A fourth line of evidence on the present topic is found in the following single observation published now four months ago. Benoit removed the single left ovary from two young chicks when four days and twenty-six days old. Several months later these birds were killed and each was found to have developed testicular tissue on the right side of the body. In these cases there can be no presumption of a cytological foundation for the development of testicular tissue. In physiological terms, however, it can be said that the removal of the restraining influence of the growing left ovary permitted the growth of testicular tissue at the point-on the right side-where testis develops best and where ovarian tissue is most retarded (the common fowl is a form in which there is evidence that the fully developed right testis is larger than the left). The four very different kinds of evidence thus briefly mentioned, together with still other considerations not practicable to include here, all become harmonized in their suggestion that the easier and more frequent appearance (and sometimes or often a greater amount) of testicular tissue on the right side of the bird's body is a matter which rests upon a physiological rather than a genetical basis; that testis develops better than ovary on the right side; and that ovarian development is more favored than testicular development on the left side of the bird's body. It is thought that no known fact is opposed to any part of this suggestion. Something may be said concerning a possible explanation of this positional differential. Though a definite explanation can not now be given, this discussion requires the mention of three points which to us seem a probable basis of the observed difference. First, Firket and Swift have shown that in the early embryo of the bird more primordial germ cells" constantly collect at the future site of the left gonad. These cells constitute the "Keimbahn" in birds and play a leading part in the entire history of the gonad; at an early stage these cells enter the embryonic blood vessels and for some unknown reason two to five times as many of them find lodgment at the seat of the left gonad as at the right. The conditions which determine this unequal distribution of primordial germ cells is probably the first condition causally related to the asymmetrical gonad growth which has been discussed in this paper. After an unequal accumulation of these cells has occurred on the two sides of the embryo it may be presumed that this inequality then itself enters into the establishment of further conditions unequally favorable to gonad growth on the right and left sides. A second point which may find application here has already been suggested by Benoit. Benoit believes that the results of his castration experiments cited above really indicate a more ready formation of testis tissue on the right side than on the left, and in explanation he cites Firket's conclusion that only the first proliferation of sex cords occurs in the right ovary of the fowl. Since only the one set of cords form in the male gonad (testis) while two form in the functional female gonad (left ovary), it is suggested that this circumstance makes easier the origin of testicular tissue from the right than from the left ovary. We agree with Benoit that a fact of real importance is probably involved in the difference just described. The facts as found by Firket for the fowl cannot, however, apply fully to our numerous cases of pigeons with numerous oöcytes in their (persistent) right ovaries; for, in these ovaries a second proliferation of sex cords has obviously occurred but such right ovaries nevertheless remain always much smaller and much less active than their associated left ovaries. We should prefer to regard an ovary in which only one instead of two proliferations of sex cords has occurred as simply less completely differentiated ovarian tissue. On the one hand, its lesser differentiation is in some way associated with its position; on the other, it is associated with greater ease of transformation into differentiated tissue of another kind, namely testis. A third consideration touches the possible existence and effects of a dissimilar or unequal blood supply to the two gonad areas of the embryo and to the gonads themselves in later stages. It is well known that in many vertebrates the vascularization of the two adult gonads is not identical. As already indicated above, the analysis of this situation requires additional facts. That the nature and amount of the blood supply to the differentiating gonad may be of importance to the type of resulting gonad is indicated by several facts, but we here cite only one. Meyns observed within testis tissue of a younger frog transplanted upon an older member of the same species that a few ova developed within the transplanted testis. The common experience with tissue transplants warrants the deduction that the testis cells which later developed into ova had meanwhile been forced to undergo a period of rigorously diminished blood supply. Such a reduction of the blood supply is a circumstance which should tend to bring about a lower metabolic rate within many of the cells of the transplant; and a lower metabolic rate is the precise condition which has earlier been found by the writer to characterize both the female organism and the female sexual cells. CARNEGIE STATION FOR EXPERIMENTAL EVOLUTION, THE SCIENTIST AND AN INTERNATIONAL LANGUAGE. BY ROLAND G. KENT, (Read April 24, 1924.) From the time of the philosophers Descartes and Leibnitz, men of various lands have sought to contrive a language for international or universal use; they have put forward more or less perfected sketches of such media of communication, to the number of over one hundred, but nothing that has received general acceptance. Yet the problem that they have been attacking is a very real one, which cannot be ignored by the scholar nor by the statesman or the merchant. What I wish to say to-day, however, concerns but one aspect of this problem: namely, in how far the scientist, and I mean by this the scholar in natural or physical sciences especially, has need of an international language, what services he has a right to expect from it, what type of language is best fitted for the task, and to what extent it can satisfy his just expectations. It is to within a comparatively recent time that the scholarly and scientific world still had an international language. There was a language used in common by many scholars of different countries. and of different tongues; for example, by the Pole Copernicus (1473– 1543), by the Swiss Bauhin (1560-1624), by the Italian Galileo (1564-1642), by the German Kepler (1571-1630), by the Englishman Hobbes (1588-1679), by the Frenchman Descartes (15961650), by the Englishman Milton (1608-1674), by the Irishman Robert Boyle (1627–1691), by the Englishmen Locke (1632-1704) and Newton (1642-1727), by the German Leibnitz (1646-1716), by the Swede Linnæus (1707-1778) by the Italian Galvani (1737– 1798) if they did not write their important works in Latin, but in the local vernacular, they would immediately thereafter translate them into Latin, to make them available to the scholars of other countries. These are moreover men from eight countries, represent ing six different tongues, and the writings for whose sake I mention them here, are works in philosophy, politics and economics, mathematics, astronomy, botany, zoology, physiology: the great scholars and the great scientific works of nearly three centuries, coming down to within a century and a half of the present time. Men still living may have talked with men who knew Linnæus; and he wrote nearly all of his many volumes in Latin. Galvani's famous treatise on the effect of electricity on muscular activity was published in Latin, in 1791, thirteen years after the death of Linnæus. But Latin is no longer used as the international language of the scientist. More and more it was abandoned for the vernacular of the country--French, English, Italian, German. Now as long as important scientific publications were restricted even to these four languages, with Latin as a possible fifth, the situation was not unbearable. It may be a task of some magnitude to acquire a ready reading command of these languages; it is not so onerous as to make it virtually impossible, even to the scientist whose interest is not in the forms and the manifestations of human expression, but in the content of such expression. But within the last century or less, other languages have come into use for scientific publication: Spanish, Dutch, Danish, Swedish, Modern Greek. These I mention from my own experience with the fruits of research in the linguistic field: I have no doubt that the natural scientist meets them in his technical literature. I have even known or heard of scientists who had learned, or were learning, Russian, Polish, Czechish, Roumanian, that they might make available to themselves the treatises in these languages. To-day, with the recrudescence of many minor nationalities, and the revived national feeling of some larger units, caused by the Great War, we may be facing an era in which important publications will appear in Finnish, Lithuanian, Hungarian, Serbian, Irish, Turkish, Hebrew, Arabic, Hindustani, Japanese, Chinese. And, alas, the salutary practice of giving in French or in English or in German, at the close of the treatise, a summary of the argument and of its results, has almost or quite disappeared. The burden has become too great, even for the professional philologist and litterateur, and means must be sought to lighten it. The |