526 Hoyal Society — Dr. Martin Barry's 



mon method as its source (pp. 93-96) ; whereas Mr. Horner's in- 

 vestigation, though perfectly valid, rested on considerations too ele- 

 vated for the supposed progress of the student. We Avere also much 

 struck w^ith the very simple and perfectly general method of inves- 

 tigating the criteria of DeGua and Budon for the reality of the roots 

 in any given interval. 



The new and extremely elegant solution of the singular problem, 

 known as Colonel Titus's problem, given by Mr. Davies, well de- 

 serves attention. A singular fact with respect to the history of this 

 problem was discovered by Mr. Halliwell in a MS. in the British 

 Museum*. It appears that Harriot was the originator of it, and 

 that it was proposed as early as the year 1 649 by William Brereton, 

 who was one of Harriot's pupils. 



Here we close our brief memoranda on a work which is certainly 

 one of the most valuable in its kind that has ever appeared. The 

 style in which it is written, and its entire conception, bespeaks no 

 ordinary mind ; and though, from the author's reputation, we should 

 have expected a work superior to those generally published with the 

 same professed objects, yet our expectations did not reach to the 

 possibility of so varied a mass of information being couched under 

 such a form as that to which the author was tied down by the na- 

 ture of his undertaking. We only regret that his limits prevented 

 him from continuing his original plan of giving varied solutions and 

 entering into the history of the different branches of elementary ma- 

 thematics. We venture to hope that at some future period this latter 

 part of the plan may be accomplished in another form. 



LXXXI. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



May 7, A PAPER was read, entitled " Researches in Embryology, 

 1 84-0. -'^ Third Series : a Contribution to the Physiology of Cells." 

 By Martin Barry, M.D., F.R.S., F.R.S.E., Fellow of the Royal 

 College of Physicians in Edinburgh. 



In the second series of these researches, the author had traced 

 certain changes in the mammiferous ovum consequent on fecunda- 

 tion. The object of his present communication is to describe their 

 further appearances obtained by the application of higher magnify- 

 ing powers ; and to make known a remarkable process of develop- 

 ment thus discovered. In order to obtain more exact results, his 

 observations were still made on the same animal as before, namely, 

 the rabbit, in the expectation that, if his labours were success- 

 ful, it would be comparatively easy to trace the changes in 

 other mammals. By pursuing the method of obtaining and pre- 

 serving ova from the Fallopian tube which he recommended in his 

 last paper, he has been enabled to find and examine 137 more of 



* Life of Sir Samuel Morland, p. 2S. 



