frontal lobe rarely produce definite focal symptoms; although, under tile same conditions as obtained in ab.scess of the temporal lobe, herni plegia of the other side of the body and aphasia may result as distal effects. An abscess in the parietal lobe, particularly one of traumatic origin, may lead to cortical convulsions and herniplegia on the opposite side of thc body, which often attacks the individual extremities in sue eeSSi011, With convulsions and fever. Abscesses in the occipital lobe are rare; they lead to hemianopsia. but the s3;mptom is not reliable. In abscesses involving both the occipital lobes blindness is observed. The characteristic symptoms of cerebellar abscess are rigidity of the neck, interference with the gait, vomiting, violent headache, and distal symptoms referable to the corpora quachigenfina, the pons and the medulla oblongata, with paralysis of the ocular muscles, the bulbar nerves, hemiplegia of the opposite si,le or paraplegia. These disturbances are observed ehiefiy when the lesion involves the worm; when the ab scess is situated in the cerebellar hemispheres, local disturbances may be absent for a long time. In the pops ancl medulla oblongata, abscesses are very rare Tassierer).
ThIs stage of manifest symptoms, which is characterized by a great variety of morbid phenomena, may merge directly into the terminal stag,e by a .stc•ady increase in the symptoms; or the terminal stage may follow immediately upon the period of latency. The pus may find its way to the surface of the brain and set up acute purulent meningitis, with convulsions, chills, acceleration of the pulse, fever and disturbances of the respiration, or the abscess may rupture into the ventricles of the brain (pyocephalus), in which case the course is exceedingly vio lent and the above-mentioned symptoms are very intense. The patient goes into collapse almost at once and death ensues a few hours later. In rare cases the terminal symptoms are less pronounced, so that a diagnosis of "atypical" meningitis is made. Again, the brain symptoms may be entirely absent and death may occur from general marasmus and pyremia.
In order to establish the diagnosis of brain abscess there must be, as Oppertheim quite properly contends, an exciting cause. In the ease of children, however, it is often difficult to find the cause as diseases of the ear and nose frequently remain latent, and a long interval often intervenes between an injury to the head and the appearance of brain abscess. Conver.sely, pus-retention foliating a head injury or an acute otitis may produce brain symptoms which promptly subside after the pus has been evacuated by surgical intervention. Even if the diagnosis of intracranial suppuration is positive, there still remain to be con sidered purulent meningitis and sinus phlebitis. Purulent meningitis is
quicker to develop after an injury or the onset of an acute otitis then is the case with brain abscess, which requires several davs or weeks to form. Acute brain symptoms suet) as convulsions, delirium and coma are more intense from the beginning and are constant; the local symp toms are more evanescent. The fluid obtained by lumbar puncture, which may be performed even if abscess is stispected, contains pus cor puscles. The diagnosis of serous meningitis, which may also occur after °title affections, is more difficult. Its symptoms are such, how ever, that there is more danger of confusing it with purulent meningitis than with brain abscess. Sinus phlebitis is characterized by a typical pus-temperature, with chills and remissions; the only positive symp toms are those referable to the blood vessels, which will be discussed in another place.
If the case is one of chronic. brain abscess, the possibility of a brain tumor must be considered, particularly as in scrofulous and tuberculous individuals the association of brain tubercle with discharge from the ears is quite within the bounds of possibility. The absence of the initial rise of temperature, the more localized eharacter of the focal symptoms and distinctly slower course of the disease, the presence of marked choked dise are in favor of brain tumor. The probable seat cif the sus pected neoplasm is of some importance, as abscess is rarely situated in the pons or in the medulla oblongata, while, on the other hand, brain tumors in children are not infrequent in these regions. If, in the pres ence of an aural affection, symptoms referable to the temporal lobes are detected, this is in favor of brain abscess. If the brain symptoms persist for some tiine without undergoing any change and the general condition 16 not favorable, the probabilities are rather in favor of an abscess. The sudden occurrence of the terminal stage, when ,symp toms of brain tumor have been present only a short time, is quite characteristic of abscess.
Even with the aid of all these points in the differential diagnosis we cannot always avoid mistakes, or at least it may have to be admitted in individual cases that the diagnosis is impossible. The fact that abscess shows a tendency to be multiple and a preference for the less characteristic portions of the brain renders its recognition more difficult. In a case of doubt between tumor and abscess it is better, in the interests of the patient, to adopt the latter theory and, if possible, to attempt operative interference.