Dept.] NATURAL SCIENCES OF PHILADELPHIA. 3 



the relative size of the " dried blood globule in man and many animals." Dr. 

 Woodward thongbt too much stress had been laid upon these measurements, 

 and conceived, that a question which it was very difficult to answer in regard 

 to fresh blood, must become almost unanswerable with dried blood. He had 

 himself been examined in a case where those concerned evidently expected that 

 the microscope would enable him to say of the specimen of dried blood, this is 

 the blood of man, or of this or that mammal. He had found himself unable to 

 decide, and had stated as his fixed opinion, that no examination by the micros- 

 cope of the blood globules fresh or dried and remoistened would enable any 

 one to swear as to the source of the specimen. He mentioned this, because in 

 this city and elsewhere other opinions are held and taught by many medical 

 men. 



Dr. Leidy stated his opinion to be the same as that held by Dr. Woodward. 

 He would feel it to be very unsafe to declare positively to what particular 

 animal certain blood corpuscles belonged. He alluded also to cases where, 

 when judicially examined, he had been obliged to correct erroneous opinions 

 similar to those spoken of by Dr. Woodward. 



Dr. Hammond agreed entirely with the opinions held by these gentlemen. 



Dr. Hartshorne stated that he had come to the same conclusion as to the im- 

 possibility of deciding positively as to the source of blood stains, with or with- 

 out the use of the microscope. 



Dr. Hammond declared that in only one class of cases did he believe that the 

 microscope could be of any service ; it would enable the physician to pro- 

 nounce with confidence that certain stains did not come from the blood of a 

 human being when the corpuscles contained therein were oval or nucleated. 



Dr. Atlee stated that he had never observed any white corpuscles in speci- 

 mens of dried blood. Drs. Leidy and Hammond added the remark, that, as far 

 as their recollection served, they had not observed them. 



Dr. Woodward declared that he had seen them very distinctly after six 

 months had elapsed, when blood had been dried rapidly on a slide. 



This difference of opinion was attributed by Dr. Morris to not using oblique 

 lights, by which these bodies are much more readily distinguished. 



2. Dr. Hammond read a paper entitled " Observations on the Colorless Blood-cor- 

 puscles," which was referred to a committee.* From a series of experiments Dr. 

 Hammond was led to infer that the white corpuscle is not so persistent in dried 

 blood as the red disc, and therefore not so capable of affording reasonable indi- 

 cations as to the presence of blood as the latter. 



III. Pathology and Pathological Anatomy. 



1. Dr. Leidy exhibited specimens of a Trichina found in the muscles 

 of a human subject. He stated that he often meets with this parasite, and, 

 most frequently, in the biceps muscle of the fore-arm. 



2. Dr. Mitchell described a gall-stone found in the gall bladder of a musk-rat. 

 It was a soft, amber-colored mass, dissolving readily in hot alcohol. As to the 

 exact nature of this substance he was not determined ; it was not, however, 

 either bile, pigment, or cholesterine. 



Dr. Uhler, as the result of very considerable study of organic substances, 

 stated he was inclined to believe that many bodies, described as such, are never 

 found in the organism during life, but are the product of chemical manipula- 

 tions. Moreover, he wished to lay stress upon the point that when vitality 



-See American Journal of the Medical Sciences, April, 1859. 

 1859.] 



