FOREIGN MICROSCOPY. 
25 
rosettes. This mode of treating the blood displays the liaBmatoblasts 
transformed into irregular, angular, stellate corpuscles, with ex- 
tremely fine delicate fibrils springing from them, branching and 
forming a network not easily seen, except they are coloured with 
iodine. Human blood exhibits these changes very plainly. The 
hsematoblasts of the ovipora, like those of the higher vertebrates, ex- 
perieuce rapid modifications. A few minutes after the prejiaration 
is made they become much changed, and may be seen in the inter- 
spaces between the haematies as little corpuscles, mostly spinous, 
isolated, or grouped in chaplets ; afterwards in small irregular masses. 
These corjjuscles are in general more highly refractive than the 
haematoblasts that form them, and are often of a greenish yellow 
colour. If blood is taken from a living animal and diffused through 
enough iodized serum to hinder coagulation, the hasmatoblasts aj^pear 
isolated and in their normal shape, but after some hours they exhibit 
small prolongations that seem formed of their own substance. In 
defribrinated blood neither haematoblasts nor their corpuscles are 
found, and this is the case with blood taken from a dead body after 
jpost mortem coagulation. The haematoblasts, as well as being destined 
to become adult red globules, possess special properties, and may be 
considered as a third species of blood elements. Are they the 
determinating cause of coagulation ? This seems probable. At any 
rate, three factors are concerned in coagulation ; a substance pro- 
ceeding by exosmose from the haematoblasts, and which perhaps 
represents paraglobulin ; isolated or grouped corpuscles formed hj 
them in the process of cadaveric change, and from which the network 
of fibrils springs ; and a substance primitively dissolved in the 
plasma, modified in the presence of the matter exuded by the haemato- 
blasts, and forming by precipitation nearly all the fibril network. In 
their normal state the smallest haematoblast corpuscles are about 1 //, 
in diameter, and the largest rarely more than 8 /x. In intense 
anaemia, especially when allied to a cachectic condition, we see 
voluminous masses formed by the haematoblasts 60 or 70 p, in their 
largest diameter, but usually the network springing from them is 
less than in the normal state. In acute maladies, the haematoblasts 
are less abundant, but, contrary to what is observed in cachexies, the 
fibrin forms a rich and thick network.* 
Action of very Low Temperature on Bacteria . — While the action of 
high temperature on bacteria has been frequently studied, few observa- 
tions have been made as to their behaviour at low temperatures, but 
it has been found that they stiffen at 0° (C.), and are not killed at 
— 18° to — 25° (C.). Herr A. Frisch by means of solid carbonic 
acid and ether exposed some putrefactive fluid bacteria and some forms 
of coccus and bacterium in* the morbid products of living organisms 
to — 87 • 5°, and allowed them in the course of 2 J hours to rise to 0°. 
The result was that the bacteria in the fluid withstood this low 
temperature, and was able to grow rapidly when transferred to a 
suitable nutritive fluid. Further information is to be given con- 
cerning the resisting power of Coccus, Bacterium, and Bacillus.f 
* ‘Comptes Reudus,’ Jan. 7, 1878. f ‘ Bcr Naturforscher,’ 5, 1878. 
