July 9. 1S96] 



.VA TV RE 



219 



paper on the development of the frog, in which he denies 

 ahogether the interpretations which Roux puts on his 

 observations ; he maintauis that all which happens when 

 one of the first two blastomeres of a frog is injured, is 

 that the wounded side is delayed in its development. If 

 the two segments are nearly separated from each other, 

 each pursues its development as if it were a complete 

 ovum. Roux's answers to these statements are two-fold : 

 first he affirms that Hertwig, through not exercising con- 

 tinuous observation, missed the scmigastrula stage, and 

 only saw the embryo after the " post-generation " or 

 'Teanimation " of the wounded half had set in ; and with 

 respect to Uriesch's work on echinoderm eggs, he suggests 

 that by separating the segments or subjecting the egg 

 to pressure, the normal machinery for bringing about 

 the development is upset, and a special regenerative 

 machinery, the reserve " idioplasson," brought into play ; 

 this occurs at a later period in the frog, but from the very 

 beginning in the echinoderm. 



It seems to us that with regard to the first point, Roux 

 still holds the field ; although we await with interest 

 further observations on this subject from such a distin- 

 guished zoologist as Hertwig. It \% a priori clear that 

 in the ordinary course of affairs one blastomere gives rise 

 to half the embryo ; and as there are a large number of 

 gradations conceivable between completely killing one 

 blastomere, and only slightly checking its growth, there 

 must be some point at which it is determined whether the 

 remaining blastomere shall develop as a whole egg or in 

 its normal manner. We cannot avoid the suspicion that 

 Roux's semigastrulae are conditioned by the contact of an 

 actively developing half, with a stunned but not killed 

 blastomere, whose influence is sufficient to prevent the 

 other half acting as a whole egg. On the other hand, 

 Roux's reply to Driesch seems to us extremely feeble. 

 To assume that by slightly altering the conditions of a 

 developing egg an entirely new machinery is brought 

 into play, is not only an altogether unproved gratuitous 

 hypothesis, but it is an attempt to discount any evidence 

 which may be gathered from physiological experiments 

 on eggs which behave differently to those of the frog. 

 When the hypothesis of " mosaic development " or " self- 

 differentiation " requires bolstering up in this fashion, it 

 must be in a bad way. 



The second volume contains a considerable number of 

 papers, comprising the whole of Rou.x's work on the 

 frog's egg. Besides the important and fundamental 

 points w-e have mentioned, we find Roux's contribution to 

 the vexed but still unsettled question of the nature of 

 gastrulation, also some extremely interesting observations 

 on the effect of alternating electric currents on the 

 unsegmented and segmented egg. As the conclusion of 

 the whole matter, Roux takes up a position decidedly 

 opposed to the theory of epigenesis ; he is in the main 

 an evolutionist, though he admits that for the complete 

 <levelopment of the organs from their embryonic 

 rudiments the functional stimuli are necessary. Uriesch 

 has also proclaimed himself an evolutionist, though he 

 points out (what Roux ssems to us to forget) that in 

 dealing with the facts of biology we must proceed 

 inductively, and not set out with preconceived ideas as to 

 the constitution of living matter. E. W. M. 



XO. 1393. VOL. 54J 



THE INDIAN CALENDAR. 

 The Indian Calendar., ■with Tables for the conversion of 

 Hindu and Muhaniinadan into A.D. dates, and vice 

 %ers;i. By Robert Sewell, late of her Majesty's Indian 

 Ci\il Service, and Saukara Balkrishna Dikshit, Train- 

 ing College, Poona. With Tables of Eclipses visible 

 in India, by Dr. Robert Schram, of Vienna. Pp. (in- 

 cluding index) 169 ; tables, &c., cxxxvi. (London : 

 Swan Sonnenschein and Co., Ltd, 1896.) 



\LTHOLlGH to many persons the chief interest of 

 this publication (which must have cost the authors 

 an amount of labour simply enormous) will be in an 

 antiquarian and historical point of view, it has another 

 aspect, judicial and practical, which was the immediate 

 cause for its appearance. Documents bearing dates prior 

 to those given in any existing almanac are often pro 

 duced before Courts of Justice in India as evidence of 

 title ; and as forgeries, many of which are of great 

 antiquity, exist in abundance, it is necessary to have at 

 hand means for testing and verifying the authenticity of 

 such documents when brought forward. Prof. Jacobi, 

 Dr. Schram, and others, have within the last ten years 

 thrown much light on the subject of the Indian methods 

 of time-reckoning ; but as their labours are only to be 

 found scattered in scientific periodicals, the results are 

 not readily accessible to officials and others to whom they 

 are of importance in enabling them to determine ques- 

 tions m which the calendar, or rather calendars, observed 

 in different parts and amongst the different peoples of 

 that vast territory known as India, play an important 

 part. Hence the Government of Madras requested Mr. 

 Sewell to undertake the formation of a summary of the 

 subject, accompanied by tables for ready reference. That 

 gentleman not only accepted the task, but enlarged the 

 scheme (which rendered it of a kind only to be called 

 herculean) so as to make it include in its scope the whole 

 of British India ; and it has received the recognition of 

 the Secretary of State for India. But besides containing 

 a full explanation of the Indian chronological systems 

 with the necessary tables for the conversion of their dates 

 into ours, and 7<ice versa, the volume is enriched by a set 

 of tables of eclipses, most kindly furnished by that great 

 authority on the subject. Dr. Robert Schram of Menna. 

 In the earlier stages of his undertaking, Mr. Sewell had 

 the assistance of Dr. J. Burgess, late Director-General of 

 the Archaeological Survey of India. Afterwards he 

 entered into correspondence with Mr. Saukara Balkrishna 

 Dikshit, of the Training College at Poona, and it was 

 agreed that the work should be completed under their 

 joint authorship. The elaborate introductory treatise is 

 mainly by Mr. Dikshit; several explanatory paragraphs, 

 however, particularly those relating to astronomical 

 phenomena, having been added by Mr. Sewell, who 

 acknowledges the assistance received from Prof. Turner 

 of Oxford, Prof. Kielhorn of Gtittingen, and Prof. Jacobi. 

 The tables of the latter were published in numbers of the 

 Indian Antiquary, and Mr. Dikshit states that his cal- 

 culations were, to a large extent, based upon these, 

 though the original scheme had been propounded by M. 

 Largeteau. We do not propose to enter into details here, 

 which cannot be made interesting to the ordinary reader. 



