With reference to your enquiry of Feb 21 concerning a sphygmograph, the only one which appears to us to answer satisfactorily for your purposes where a revolving cylinder is not available, is that of Marey, which however has received no important improvements within the last two or three years. Where a revolving drum can be used the best arrangement is that recommended by Burdon-Sanderson as described by Waller in the Journal of Physiology Vol. III Pt. 1. This little instrument we can supply if you should desire a thing of that kind. It presents vertain conveniences but appears less accurate in so far as giving the true form of the pulse wave than the improved Sphygmograph of Marey as made by Pruguet[?]. We do not make any apparatus for estimating the amount of haemoglobin, or the number of blood corpuscles, but we believe that Gower's arrangements are those which give the most satisfactory results. That of Malanez[?] for the enumeration seems now out of date. In obtaining to a imp[?] of the cartoid valve in a [illeg.] the arrangement used by Waller seems best, but as we mentioned above we do not think much of its accuracy. We have in view the making of a new instrument for this purpose but our own experiments have not yet gone sufficiently far tpo warrant our promising to supply one within a reasonable time. As a rule we do not make Instruments that can be obtained from other makers, but we are always anxious to make things from suggestions & shall be glad to work out any idea you may have on the subject.

Faithfully yours,

A.G.D. for the Company.' (f. 89)