So SCIENCE PROGRESS 



observations. In shed blood Bizzozero 1 believes that it is easy 

 in one and the same preparation to distinguish " Blutplattchen " 

 from Wooldridge's bodies, for both these, he states, occur in 

 peptone blood. The former " are swollen and granular, some- 

 what pale, collect into heaps, and on treatment with water or 

 dilute acetic acid can be differentiated into two substances; 

 a hyaline, rounded, swollen portion and a granular half-moon- 

 shaped body applied to the periphery of the hyaline part, while 

 Wooldridge's bodies are homogeneous, refract light strongly, are 

 arranged in small rosettes, and by the action of dilute acetic 

 acid become more apparent and glistening; with water they 

 vanish from the specimen." In the capillaries of the living 

 mesentery of rodents spread out in warm "6 per cent, sodium 

 chloride at 37 C, and also in an arteriole when the rapid flow 

 is checked by pressing a glass rod on the main vessel as it 

 leaves the abdomen, and therefore in blood which comes " direct 

 from the heart," Bizzozero states blood-plates can be seen. 

 Weigert's criticism of this latter experiment may be given in 

 his own words : " If it is beyond contention that under physio- 

 logical conditions blood-platelets occur in circulating blood, so 

 is it probable that the requisite manipulations produce so many 

 vascular lesions that a disintegration of the white cells of the 

 blood is induced or augmented, and when these products within 

 the circulation occur, so may any arterial branch contain these 

 platelets if, as is probable, they are disintegration products of 

 the leucocytes." 2 J. Arnold and others who have repeated these 

 experiments consider that the greater the care which is exercised 

 in preparing the mesentery the greater is the difficulty of 

 recognising any platelets within the vessels. To meet the 

 objection that injury to the mesenteric capillaries induces the 

 formation of platelets, the rhythmically pulsating vessels in 

 the patagium of two species of bats {Vcspertilio murinus and 

 Plecorus auritus) were examined by Bizzozero and Laker, 3 by 

 both of whom platelets were recognised among the red 

 corpuscles. Lowit 4 states that this experiment yielded him a 



1 " IJber die Blutplattchen," Fesischirft, Rudol Virchow, Bd. i. 1891. 



2 " Die neuesten Arbeiten iiber Blutgerinnung," Fortschulte de Medicin, i. 

 1883. 



3 " Die Blutscheiben sind constante Formelemente des normal circulirenden 

 Saugerthierblutes," Virch. Archiv, 116, 1889. 



4 " Ueber die Praexistenz der Blutplattchen und die Zahl der weissen Blut- 

 korperchen im normalem Blute des Menschen," Virch. Archiv, 117, 1889. 



