TOL. II.J PHILOSOPHICAL TRANSACTIONS. I97 



r and s, so fitted with threads t and u, that they may be conveniently used in- 

 stead of the solid edges of the sights k and i. 



The 4th figure represents how the screws are to be put on. The tube A D 

 is divided into three lengths ; of which B C is to lengthen or contract as the 

 object requires ; but A B is here added, that at A there may be put on such 

 eye-glasses as shall be thought most convenient, and, to set them always at the 

 distance most proper for them, indexes or pointers, which here are supposed to 

 be at B ; which length alters also in respect of divers persons' eyes. E is a 

 screw by which the great tube can be fixed so as by the help of the figures 

 any smaller part of it can immediately be found, measuring only or knowing 

 the divisions on B C, the distance of the object glass from the pointers. F is 

 the angular piece of wood that lies on the upper screw of the stand,* which is 

 represented by figure 5. 



For a description of the uses of this ingeniously contrived and very curious 

 engine, see No. 25, p. l6l. 



An Account of making a Dog draw his Breath exactly like a Wind- 

 broken Horse. By Dr. Richard Lower. '\ N" 29, p. 544. 



After I had often considered the manner and way of respiration, and by many 

 observations been induced to believe that the diaphragm is its chief organ, I 

 thought there could be no better way to try it, than by dividing the nerves, by 

 which its motion is performed ; which may be easily done after the following 

 manner : 



First, pierce the side of the animal between the 6th and 7 th rib in the mid- 

 dle of the thorax, just opposite the region of the heart, with a small incision- 



* This rest (by Mr. Hook's suggestion) may be rendered more convenient, if, instead of placing 

 the screw horizontal, it be so contrived that it may be laid parallel to the equinoctial, or to the diur- 

 nal motion of the earth. For by that means the same thing may be performed by the single motion 

 of one screw, which in the other way cannot be done but by the turning of both screws. 



f Richard Lower was one of the best anatomists of the 17 th century. He was educated at Oxford, 

 took his degree of M. D. in that university, and exercised his profession there for some years; but at 

 length removed to London, where he got into extensive practice. He and Dr. King appear to have 

 been the first who performed the experiment of the transfusion of blood. Besides several papers in- 

 serted in the Phil. Trans, he wrote a treatise, which procured him a great and deserved renown, De 

 Corde, item de motu et Colore Sanguinis et Chyli in eum transitu, 1669. Among other things in 

 this treatise, he pointed out the difference between arterial and venous blood, proving that tlie florid 

 colour of the arterial blood is derived from the air. Lower was very warm in his attachments, and 

 when his friend Willis's Theory of Fevers was attacked by De Meara, he wrote a Latin treatise in de- 

 fence of it. In the latter part of his life he sided with the political party in opposition to the court ; 

 a line of conduct which proved detrimental to his professional interests. 



