ON MINUTE INJECTIONS. 165 



preserved perfectly in my B fluid specific gravity 1-100; 

 the A fluid destroys them. 



" I would recommend, that the slips of glass employed for 

 the dry preparation be instantly inscribed with the name of 

 the preparation, written with a diamond, for, when dry, it is 

 very difficult to recognise one preparation from another, until 

 the operator's eye be educated to the effects of this chemico- 

 gelatinous injection. Where so much wet abounds gummed 

 paper is apt to come off. 



" When dry, it is sufficient for the purpose of brief exami- 

 nation by the microscope, to wet the surface of a preparation 

 with clean oil of turpentine; immediately after examination, 

 it should be put away carefully in a box, to keep it from the 

 dust, until it can be mounted in Canada balsam. 



" Although highly desirable, as the demonstrator of the 

 capillaries of normal tissues, I do not think this kind of injec- 

 tion fitted for morbid preparations, the infiltrated gelatine 

 producing appearances of a puzzling kind, and calculated to 

 mislead the pathologist. 



"In preparing portions of dried, well-injected skin, for exa- 

 mination by the microscope, I have tried the effect of dilute 

 nitric acid, as a corroder, with very good results. But, proba- 

 bly, liquor potassae would have answered this purpose better. 



"When size injection is to be employed, colored either with 

 vermilion or the chromate of lead, the animal should be pre- 

 viously prepared by bleeding, to empty the vessels: for if 

 they be filled with coagulated blood, it is quite impossible to 

 transmit even size, to say nothing of the coloring matter. 

 Hence the difficulty of procuring good injections of the human 

 subject. 



"But with the 'chemico-gelatinous' injections no such pre- 

 paration is necessary, and success should always be certain, for 

 the potash liquefies the blood, while constant and long-con- 



