5. The intermediate period. During this time there may be no symptom, or slighter recurrence of the secondary {312} symptoms. This period lasts from two to four years. It may end in recovery of health or be followed by tertiary symptoms. 6. The tertiary stage. In this period gummata form, or there may be diffuse infiltration of various parts of the body, chronic inflammation and ulceration of the bones, skin and other tissues, nervous diseases, and so on. The tertiary stage commonly begins from three to four years after the primary infection. The three chief divisions, which are apt to blend one into the other, are the primary, secondary, and tertiary periods. The affections of the secondary stage are often severe. There may be fever associated with weakness, headache, general malaise and pain, and this may be marked or rather light. In this stage iritis is liable to occur, and if it is not properly diagnosed and treated it will result in blindness. The lesions of the tertiary stage may cause great destruction of tissues and very grave consequences. Cerebral syphilis, if unchecked, will inevitably cause paralysis or paresis. There may be loss of speech, epilepsy, coma, paralyses, apoplectic hemiplegia, and so on. The pain is harassing and often it amounts to great anguish. Whatever part of the brain substance is destroyed will not be restored. In syphilitic affections of the spinal cord, if the inflammation is acute death ensues in a few days or weeks. _Tabes dorsalis_, or locomotor ataxia, is caused in about 93 per centum of cases of this disease by syphilis, and it is an incurable and dreadful malady. If there is neuritis from the virus it becomes intense and causes muscular contractions, paresis, and paralysis. The optic, auditory, and olfactory nerves may be attacked and destroyed. The nose also may be destroyed and it commonly caves in. The bones of the face are frequently attacked in the tertiary stage and they rot away. The tibia is diseased more frequently than the other long bones. The heart is rarely injured, but when it is, the prognosis usually is bad. In a large number of cases death is sudden and unexpected. If the arteries are involved the prognosis again is bad, because the symptoms here do not show until {313} too late for effective treatment When the liver is the seat of gummata these may be cured in the early stage, but in the later stage the prognosis is unfavourable. Some forms of renal syphilis are remediable, but others are not, especially the interstitial kind. Syphilis is transmitted to a child congenitally, not as a tendency or predisposition, but as an active contagion. It may come from the father, the mother, from both parents, or by direct infection.