Royal Society. 221 



and thus conceived that the blood-discs are of subordinate import- 

 ance, and are not concerned in the evolution of fibrin. 



To render the filament distinctly visible, Dr. Barry adds a chemi- 

 cal reagent capable of removing a portion of the red colouring 

 matter, without altogether dissolving the filament. He employs for 

 this purpose chiefly a solution of one part of nitrate of silver in 120 

 parts of distilled water ; and sometimes also the chromic acid. He 

 admits that the use of these reagents would, on account of their 

 destructive tendency when concentrated, be objectionable as proofs 

 of the absence of any visible structure ; but as the point to be 

 proved is that a certain specific structure does exist, he contends 

 that the same appearance would not equally result from the chemi- 

 cal actions of reagents so different as are those of chrome and the 

 salts of mercury and of silver. After the appearance of the fila- 

 ment, thus brought to light, has become familiar to the eye, it may 

 be discerned in the blood-discs, when coagulation has commenced, 

 without any addition whatever. Those blood-discs of the newt, 

 which contain filaments, often assume the form of flask-like vesicles, 

 the membranes of which exhibit folds, converging towards the neck, 

 where, on careful examination, a minute body may be seen pro- 

 truding. This body is the extremity of the filament in question, its 

 protrusion being occasionally such as admit of its remarkable struc- 

 ture being recognised. 



The author proceeds to describe various appearances which he 

 has observed in the coagulum of the blood, and which strongly re- 

 semble those met with in the tissues of the body, and are obviously 

 referable to a similar process of formation. He bears testimony to 

 the accuracy of the delineations of coagulated blood given by Mr. 

 Gulliver. One of the most remarkable phamomena discovered by 

 the author in the coagulation of the blood is the evolution of red 

 colouring matter ; a change corresponding to that which he had 

 previously observed to take place in the formation of the various 

 structures of the body out of the corpuscles of the blood. He con- 

 siders the production of filaments as constituting the essential cir- 

 cumstance in coagulation. 



He conjectures that the notched or granulated fibres noticed in 

 the blood by Professor Mayer, may have been of the same kind as 

 the flat, grooved, and compound filaments described by himself; but 

 he thinks that, in that case, Mayer's explanation of their mode of 

 origin must be erroneous ; for they may be seen to be produced by 

 a portion of the blood not mentioned by him, namely, the corpus- 

 cles. 



Mr. Addison's discovery of globules in the uppermost stratum of 

 inflammatory blood, and of their influence in the formation of the 

 buffy coat, is confirmed by Dr. Barry, who remarks that these glo- 

 bules are altered red blood-discs. That the blood corpuscles are 

 reproduced by means of parent-cells, as suggested by Mr. Owen 

 and by the author, is confirmed by the observations of Dr. Remak ; 

 but the author had long ago indicated a division of the nucleus as 

 being more particularly the mode of reproduction, not only of those 



